Pour voir les autres types de publications sur ce sujet consultez le lien suivant : Differential electrochemical mass spectrometry (DEMS).
Articles de revues sur le sujet « Differential electrochemical mass spectrometry (DEMS) »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleurs articles de revues pour votre recherche sur le sujet « Differential electrochemical mass spectrometry (DEMS) ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les articles de revues sur diverses disciplines et organisez correctement votre bibliographie.
1
Clark, Ezra L. « (Invited) Investigations of Electrochemical CO2 Reduction with Differential Electrochemical Mass Spectrometry ». ECS Meeting Abstracts MA2023-01, no 26 (28 août 2023) : 1720. http://dx.doi.org/10.1149/ma2023-01261720mtgabs.
Texte intégralRésumé :
Differential electrochemical mass spectrometry (DEMS) is an analytical technique wherein an electrochemical reactor is interfaced with a mass spectrometer using a pervaporation membrane. This configuration enables volatile electrochemical reaction products to be continuously collected, identified, and quantified during steady state and dynamic polarization. The capabilities of this analytical technique are highly dependent on the design of the electrochemical reactor and how it is interfaced to the mass spectrometer. This presentation will introduce a variety of different DEMS cell designs and will compare their capabilities and limitations in terms of product sensitivity, product quantifiability, and time response. These comparisons will be illustrated through a series of vignettes investigating the electrocatalysis of CO2 reduction over Cu, Ag, and Au. This reaction is particularly difficult to investigate with DEMS since many of the reaction products yield identical mass fragments upon electron impact ionization. A general strategy for deconvoluting the extent to which a given product contributes to the observed mass ion currents will be presented. The utilization of DEMS for the direct observation of both the composition of the local reaction environment and the transient formation of intermediate reaction products will be discussed, as well as how these insights can be leveraged to guide rational electrocatalyst design. Finally, a new type of DEMS setup capable of quantifying the steady state surface coverage and surface lifetimes of electrochemical reaction intermediates will be presented. Figure 1
2
Goyal, Akansha, Christoph J. Bondue, Matthias Graf et Marc T. M. Koper. « Effect of pore diameter and length on electrochemical CO2 reduction reaction at nanoporous gold catalysts ». Chemical Science 13, no 11 (2022) : 3288–98. http://dx.doi.org/10.1039/d1sc05743j.
Texte intégralRésumé :
In this work, we employ differential electrochemical mass spectrometry (DEMS) to track the real-time evolution of CO at nanoporous gold (NpAu) catalysts with varying pore parameters (diameter and length) during the electrochemical CO2 reduction reaction (CO2RR).
3
Shimizu, Shugo, Atsunori Ikezawa, Takeyoshi Okajima et Hajime Arai. « Quantitative Differential Electrochemical Mass Spectroscopy Analysis of Electrochemical Carbon Corrosion Reactions in Alkaline Electrolyte Solutions ». ECS Meeting Abstracts MA2024-02, no 60 (22 novembre 2024) : 4054. https://doi.org/10.1149/ma2024-02604054mtgabs.
Texte intégralRésumé :
Introduction Zinc-air secondary batteries are attracting attention as next-generation large-scale energy storage devices. However, one of the challenges for practical application is the prevention of air electrode degradation caused by the oxidative corrosion of carbon. In order to suppress the carbon corrosion reaction, clarification of the reaction mechanism is required. The differential electrochemical mass spectrometry (DEMS) is the in-situ mass spectrometry for the volatile species generated by electrochemical reactions, and it is possible to measure the partial current of the carbon corrosion reaction by analyzing CO2 evolution. Therefore, DEMS has intensively been applied to carbon corrosion reactions under acidic conditions. However, applying DEMS to alkaline electrolyte systems is challenging due to the relatively high solubility of CO2 as carbonate ions. On the other hand, we have constructed a new DEMS measurement system combining a microreactor and an ion-exchange membrane and quantitatively analyzed CO2 evolution in an alkaline aqueous solution [1]. However, the current measurement system had relatively low temporal resolution and large IR-drop. In this study, we constructed the DEMS measurement system with improved temporal resolution and reduced IR-drop. Experimental A schematicof the electrochemical three-electrode cell used for the DEMS measurement is shown in Fig.1.A platinum-supported carbon composite electrode, a Hg/HgO electrode, a Pt wire, and 1 mol dm–3 KOH solution were used as the working, reference, and counter electrodes and the electrolyte solution, respectively. The electrolyte solution was flown into the cell using a syringe pump and acidified with a 1 mol dm–3 sulfuric acid solution in a microreactor installed downstream of the working electrode. The volatile components were installed from the electrolyte solution to the vacuumed chamber through a PTFE membrane interface placed at the downstream of the microreactor. The electrolyte path from the working electrode to the membrane interface was shortened from 13.5 cm to 4.5 cm to improve the temporal resolution of the previous system. In addition, the position of the reference electrode was changed from the outside of the working electrode chamber to inside of that to reduce the IR-drop at the ion-exchange membrane. We also increase the working electrode area from 78.5 mm2 to 201 mm2 in order to enhance the detectivity. CO stripping voltammetry (Eq. (1)) was performed to evaluate the CO2 detection property of the constructed DEMS system. Pt-COad + 2OH– → Pt* + CO2 + H2O + 2e– (1) Results and discussion Fig.1 shows the CO stripping voltammogram and the corresponding mass signal of CO2. CO oxidation current is observed from –0.5 to –0.2 V, while our previous setup showed CO oxidation current from –0.4 to 0.1 V [1]. This result shows that the IR-drop is effectively suppressed in the new DEMS setup. In addition, the mass signal of CO2 is observed in the almost same potential range (–0.5 to –0.1 V) as that of the CO oxidation current, suggesting that the new DEMS setup has improved temporal resolution. On the other hand, the calibration constant (Eq. 2) of new DEMS setup is to the same extent as the previous one [1], indicating that the new DEMS setup has the comparable detectivity. Analyses of catalyst-loading carbon corrosions will also be presented at the site. References [1] A. Ikezawa, J. Kida, K. Miyazaki, H. Arai, Electrochem. Commun., 159, 107647_1-6 (2024). This work was partially supported by JSPS KAKENHI (JP23K13819) JRP-LEAD with DFG (JPJSJRP20221602) Figure 1
4
Kim, Dong Wook, Su Mi Ahn, Jungwon Kang, Jungdon Suk, Hwan Kyu Kim et Yongku Kang. « In situ real-time and quantitative investigation on the stability of non-aqueous lithium oxygen battery electrolytes ». Journal of Materials Chemistry A 4, no 17 (2016) : 6332–41. http://dx.doi.org/10.1039/c6ta00371k.
Texte intégralRésumé :
Differential electrochemical mass spectrometry (DEMS) results clearly show that dimethylacetamide (DMA) is more stable and exhibits better performance than tetraethylene glycol dimethyl ether (TEGDME), suggesting that DMA is a more favorable electrolyte for Li–O2 battery applications.
5
Queiroz, Adriana, Wanderson Oliveira da Silva, Daniel Cantane, Igor Messias, Maria Rodrigues Pinto, Fabio De Lima et Raphael Nagao. « Building a Differential Electrochemical Mass Spectrometry (DEMS) : A Powerful Toll for Investigation of (photo)Electrochemical Processes ». ECS Meeting Abstracts MA2021-01, no 46 (30 mai 2021) : 1873. http://dx.doi.org/10.1149/ma2021-01461873mtgabs.
Texte intégral
6
Cuomo, Angelina, Pavlo Nikolaienko et Karl J. J. Mayrhofer. « Designing a Novel Setup for High-Throughput Investigations of Electrochemical Reactions in Real Time ». ECS Meeting Abstracts MA2023-02, no 55 (22 décembre 2023) : 2702. http://dx.doi.org/10.1149/ma2023-02552702mtgabs.
Texte intégralRésumé :
With the great interest in new electrochemical processes, fast screening of various reaction parameters is highly desirable. For this purpose, differential electrochemical mass spectrometry (DEMS) and membrane-inlet mass spectrometry (MIMS) have been established to enable real-time monitoring of volatile compounds. However, the analysis of non-volatile compounds is commonly limited by the temporal resolution of traditional quantification methods such as NMR, GC-MS, or LC-MS. While ambient ionization mass spectrometry (AIMS) generally enables time-resolved monitoring of non-volatile compounds, electrolyte salts can lead to ionization suppression. The latter can decrease the sensitivity of product detection and the reliability of quantitative data. Therefore, a suitable reaction setup and thorough investigations are needed when utilizing AIMS. Nonetheless, in recent efforts, an electrochemical flow cell was coupled with such a technique to provide a method for on-line monitoring of non-voltile reaction products in aqueous electrolytes. To keep up with the increasing interest in electrosynthesis in organic media, we now present a new setup that is also applicable to non-aqueous media. It pairs a novel and versatile electrochemical cell with an AIMS and DEMS for highly sensitive detection of reaction products. Moreover, various reaction parameters such as electrode material, electrolyte, and temperature can be investigated in high-throughput. Key words: Electrocatalysis, Electrosynthesis, Real-time, On-line monitoring, High-throughput
7
Celorrio, V., L. Calvillo, R. Moliner, E. Pastor et M. J. Lázaro. « Carbon nanocoils as catalysts support for methanol electrooxidation : A Differential Electrochemical Mass Spectrometry (DEMS) study ». Journal of Power Sources 239 (octobre 2013) : 72–80. http://dx.doi.org/10.1016/j.jpowsour.2013.03.037.
Texte intégral
8
Winiwarter, Anna, Kim Degn Jensen et Johannes Novak Hartmann. « Quantitative Electrochemistry-Mass Spectrometry : Real-Time Detection of Volatile Products for Electrocatalysis and Batteries ». ECS Meeting Abstracts MA2023-01, no 48 (28 août 2023) : 2537. http://dx.doi.org/10.1149/ma2023-01482537mtgabs.
Texte intégralRésumé :
A major challenge both within electrocatalysis and battery research concerns the real-time (i) identification and (ii) quantification of volatile reaction products as a function of the applied electrochemical parameters and the reaction conditions. Analysis of both steadily evolving gases and of fast- and transient reaction phenomena can reveal key insights into reaction mechanisms. To this end, methods like Differential Electrochemical Mass Spectrometry (DEMS)1 and On-line Electrochemical Mass Spectrometry (OLEMS)2 have been used successfully to study reaction mechanisms to an ever-increasing degree in recent years, primarily in aqueous electrolytes. Similarly, Online Electrochemical Mass Spectrometers (OEMS)3 have been essential for the study of gas evolution in batteries. However, to gain an in-depth understanding of these mechanisms, the ability to accurately relate the electrochemical charge transferred in the reaction to the amount of evolved product is essential. To this end, accurate calibration of MS signals is paramount. Calibration procedures available for DEMS systems are by themselves cumbersome and unreliable and full quantification is not possible for OLEMS. Herein, we show how a simple gas-based calibration procedure using chip-based Electrochemistry-Mass Spectrometry (EC-MS) can be used for reliable, fully quantitative real-time analysis of volatile electrochemical reaction products. We validate this calibration with electrochemistry-based calibration methods described previously.4,5 The new procedure allows to extend the quantitative analysis to systems with no a priori knowledge of faradaic efficiencies. We demonstrate calibration of important gases like H2, O2 and C2H4 in aqueous and non-aqueous electrolytes and exemplify the calibration methodology’s usefulness on standard electrochemical reactions. References H. Baltruschat, J Am Soc Mass Spectrom, 15, 1693–1706 (2004). A. H. Wonders, T. H. M. Housmans, V. Rosca, and M. T. M. Koper, J Appl Electrochem, 36, 1215–1221 (2006). N. Tsiouvaras, S. Meini, I. Buchberger, and H. A. Gasteiger, J Electrochem Soc, 160, A471–A477 (2013). D. B. Trimarco et al., Electrochim Acta, 268 (2018). S. B. Scott, PhD thesis, Technical University of Denmark (2019). Figure 1: a) Schematic of the MS inlet chip’s working principle. b) Uncalibrated M2 and M32 signals (dotted lines) and the same signals after calibration for H2 and O2 (full lines) in a cyclic voltammogram of PtPoly in 0.1 M HClO4 obtained at room temperature at 20 mV/s. Figure 1
9
Musilová-Kebrlová, Natálie, Pavel Janderka et Libuše Trnková. « Electrochemical processes of adsorbed chlorobenzene and fluorobenzene on a platinum polycrystalline electrode ». Collection of Czechoslovak Chemical Communications 74, no 4 (2009) : 611–25. http://dx.doi.org/10.1135/cccc2008221.
Texte intégralRésumé :
The electrode processes of chlorobenzene (CB) and fluorobenzene (FB) on polycrystalline platinum (Pt-pc) electrode in sulfuric acid were studied by differential electrochemical mass spectrometry (DEMS). Contrary to the oxidation of adsorbed benzene on Pt surface, the oxidation of adsorbed CB and FB in the oxygen adsorption region does not provide solely CO2 as the final product. At negative polarization potentials CB and FB were desorbed under dehalogenation. While in the case of FB only benzene was detected, CB gave intermediates besides benzene. The final product of stepwise hydrogenation of these species was cyclohexane.
10
Amin, Hatem M. A., et Helmut Baltruschat. « How many surface atoms in Co3O4 take part in oxygen evolution ? Isotope labeling together with differential electrochemical mass spectrometry ». Physical Chemistry Chemical Physics 19, no 37 (2017) : 25527–36. http://dx.doi.org/10.1039/c7cp03914j.
Texte intégral
11
Hariyanto, H., Widodo W. Purwanto et Roekmijati W. Soemantojo. « CO2 current efficiency in direct ethanol fuel cell ». Jurnal Teknik Kimia Indonesia 6, no 1 (2 octobre 2018) : 581. http://dx.doi.org/10.5614/jtki.2007.6.1.6.
Texte intégralRésumé :
In this present work, a systematically study on 20% PtCeO2/C catalyst for ethanol electro-oxidation in direct ethanol fuel cell were carried out. For cathode catalyst, a commercial catalyst of 40% Pt/C from ETEK was applied. Catalysts were printed on to carbon paper of TGPH 060 and sandwiched into membrane electrode assembly (MEA) and then arranged infitel cell with the geometric area 1.2 cm2. As an electrolyte, we used Nafion 117 from Du Pont. On-line Differential Electrochemical Mass Spectrometry (DEMS) measurement infuel cell setup was carried out in order to determine the activity and selectivity which was indicated by result of Faradaic current and CO2 current efficiency of ethanol electro-oxidation respectively. PtCeO2/C was significantly improving the selectivity of CO formation n comparison to the commercial catalyst of 20% Pt/C from A/fa Aesar- Johnson Mattews. Increasing of" selectivity was shown by the increase of CO2 current efficiency of ethanol oxidation of about 20 percent in comparison to references catalyst of 20% Pt/C (AlfaAesar-JM).Keywords: Ceria, Membrane Electrode Assembly (MEA), DEMS, Ethanol Electro-OxidationAbstrakPada peneletian ini dilakukan kajian sistematis terhadap katalis 20% PtCeO2/C yang akan digunakan pada elektro-oksidasi etanol pada sel bahan bakar etanol langsung. Untuk katalis katoda, digunakan katalis komersial 40% Pt/C dari ETEK. Katalis tersebut diaplikasikan pada kertas karbon TGPH 060 dan diselipkan pada rangkaian membran electroda (MEA) dan kemudian disusun pada sel bahan bakar yang memiliki luas geometris 1.2 cm2. Sebagai elektrolit, digunakan Nafion 117 produksi Du Pont. Pengukuran On-line oleh Spektrometri Massa Elektrokimia Diferensial atau Differential Electrochemical Mass Spectrometry (DEMS) pada pemasangan sel bahan bakar telah dilakukan untuk menentukan aktivitas dan selektivitasnya yang dapat ditunjukkan masing-masing oleh hasil arus Faradik dan efisiensi arus CO2 dari elektro-oksidasi etanol. Dari hasil percobaan diperoleh bahwa PtCeO2/C dapat secara signifikan meningkatkan selektivitas untuk membentuk CO2 dibandingkan terhadap katalis komersial 20% Pt/C dari A/fa Aesar-Johnson Mattews. Kenaikan selektivitas ditunjukkan oleh kenaikan efisiensi arus CO2pada oksidasi ethanol sebesar 20 persen dibandingkan terhadap katalis rujukan 20% Pt/C (AlfaAesar-JM).Kata Kunci: Ceria, Membrane Electrode Assembly (MEA), DEMS, Elektro-Oksidasi Etanol
12
Ikezawa, Atsunori, Juri Kida, Shugo Shimizu et Hajime Arai. « Quantitative Analysis of CO2 Evolution in an Alkaline Electrolyte Solution By Differential Electrochemical Mass Spectroscopy ». ECS Meeting Abstracts MA2023-02, no 55 (22 décembre 2023) : 2686. http://dx.doi.org/10.1149/ma2023-02552686mtgabs.
Texte intégralRésumé :
CO2 is involved in various main and side reactions of electrochemical energy devices, such as carbon corrosion reactions and alcohol oxidation reactions. Differential electrochemical mass spectroscopy (DEMS) has been intensively applied in acidic electrolyte solutions to analyze these reactions. DEMS is the in-situ electrochemical measurement technique to analyze volatile species with the mass spectrometer (MS). However, the applications of DEMS to alkaline electrolyte solutions have been limited due to the high solubility of CO2 in alkaline solutions. While "conventional DEMS cells," where porous thin-film working electrodes are formed onto polytetrafluoroethylene (PTFE) membrane interface, can quantitatively analyze CO2 that has not dissolved into the electrolyte yet [1], the working electrode materials are limited to those that can be deposited on porous PTFE membrane as porous thin-films. Recently, Möller et al. have developed the DEMS system, which can detect CO2 from general planer electrodes coated by catalyst powders by combining a neutralizer and "dual thin-layer flow cell" [2]. However, due to the relatively low detection limit, quantitative analysis of evolved CO2 has not been accomplished. In this study, we attempt to use high surface area electrodes to enhance the MS signal of CO2 to enable quantitative analysis of evolved CO2. To suppress the in-plane reaction distribution in the flow cell, we integrated an anion exchange membrane into the cell and arranged the counter electrode opposing the working electrode [3] (Fig. 1 (a)). CO-stripping voltammetry was performed to evaluate the CO2 detectability of the constructed DEMS system. The DEMS cell was composed of a commercial Pt/C electrode as the working electrode, a commercial Hg/HgO electrode as the reference electrode, a Pt mesh as the reference electrode, 1 mol dm–3 KOH aq as the electrolyte solution, and 1 mol dm–3 H2SO4 aq as the neutralizer. Figure 1 (b) shows the CO-stripping voltammogram and corresponding MS signal of CO2 (m/z = 44). MS signal of CO2 accompanied by the anodic CO oxidation current is clearly observed from 0.6 to 1.2 V vs. RHE. The calibration constant, which correlates the MS signal of CO2 to partial current for CO2 evolution reaction, is successfully obtained as 2.2 × 10–10, which shows that the DEMS system established in this study can quantitatively analyze CO2. Applications to the carbon corrosion reactions are also presented at the site. References [1] D. Bayer et al., Int. J. Hydrog. Energy, 35, 12660 (2010). [2] S. Möller et al., Angew. Chem. Int. Ed., 59, 1585 (2020). [3] E. L. Clark et al., Anal. Chem., 87, 8013 (2015). Figure 1
13
Brimaud, Sylvain, Zenonas Jusys et R. Jürgen Behm. « Shape-selected nanocrystals for in situ spectro-electrochemistry studies on structurally well defined surfaces under controlled electrolyte transport : A combined in situ ATR-FTIR/online DEMS investigation of CO electrooxidation on Pt ». Beilstein Journal of Nanotechnology 5 (28 mai 2014) : 735–46. http://dx.doi.org/10.3762/bjnano.5.86.
Texte intégralRésumé :
The suitability and potential of shape selected nanocrystals for in situ spectro-electrochemical and in particular spectro-electrocatalytic studies on structurally well defined electrodes under enforced and controlled electrolyte mass transport will be demonstrated, using Pt nanocrystals prepared by colloidal synthesis procedures and a flow cell set-up allowing simultaneous measurements of the Faradaic current, FTIR spectroscopy of adsorbed reaction intermediates and side products in an attenuated total reflection configuration (ATR-FTIRS) and differential electrochemical mass spectrometry (DEMS) measurements of volatile reaction products. Batches of shape-selected Pt nanocrystals with different shapes and hence different surface structures were prepared and structurally characterized by transmission electron microscopy (TEM) and electrochemical methods. The potential for in situ spectro-electrocatalytic studies is illustrated for COad oxidation on Pt nanocrystal surfaces, where we could separate contributions from two processes occurring simultaneously, oxidative COad removal and re-adsorption of (bi)sulfate anions, and reveal a distinct structure sensitivity in these processes and also in the structural implications of (bi)sulfate re-adsorption on the CO adlayer.
14
Mora-Hernandez, J. M., Williams I. González-Suárez, Arturo Manzo-Robledo et Mayra Luna-Trujillo. « A comparative differential electrochemical mass spectrometry (DEMS) study towards the CO2 reduction on Pd, Cu, and Sn -based electrocatalyst ». Journal of CO2 Utilization 47 (mai 2021) : 101504. http://dx.doi.org/10.1016/j.jcou.2021.101504.
Texte intégral
15
Bayer, Domnik, Florina Jung, Birgit Kintzel, Martin Joos, Carsten Cremers, Dierk Martin, Jörg Bernard et Jens Tübke. « On the Use of Potential Denaturing Agents for Ethanol in Direct Ethanol Fuel Cells ». International Journal of Electrochemistry 2011 (2011) : 1–8. http://dx.doi.org/10.4061/2011/154039.
Texte intégralRésumé :
Acidic or alkaline direct ethanol fuel cells (DEFCs) can be a sustainable alternative for power generation if they are fuelled with bio-ethanol. However, in order to keep the fuel cheap, ethanol has to be exempted from tax on spirits by denaturing. In this investigation the potential denaturing agents fusel oil, tert-butyl ethyl ether, and Bitrex were tested with regard to their compatibility with fuel cells. Experiments were carried out both in sulphuric acid and potassium hydroxide solution. Beside, basic electrochemical tests, differential electrochemical mass spectrometry (DEMS) and fuel cell tests were conducted. It was found that fusel oil is not suitable as denaturing agent for DEFC. However, tert-butyl ethyl ether does not seem to hinder the ethanol conversion as much. Finally, a mixture of tert-butyl ethyl ether and Bitrex can be proposed as promising candidate as denaturing agent for use in acidic and alkaline DEFC.
16
Crafton, Matthew J., Zijian Cai, Tzu-Yang Huang, Zachary M. Konz, Ning Guo, Wei Tong, Gerbrand Ceder et Bryan D. McCloskey. « Dialing in the Voltage Window : Reconciling Interfacial Degradation and Cycling Performance Decay with Cation-Disordered Rocksalt Cathodes ». ECS Meeting Abstracts MA2023-01, no 2 (28 août 2023) : 636. http://dx.doi.org/10.1149/ma2023-012636mtgabs.
Texte intégralRésumé :
Lithium-excess, cation-disordered rocksalt (DRX) materials have received considerable interest as cathode materials for Li-ion batteries, owing to their high specific capacity and compositional flexibility. Despite these advantages, high interfacial reactivity of DRX materials causes extensive oxidative electrolyte degradation at the cathode-electrolyte interface. In addition to consuming electrolyte, this interfacial degradation is likely to lead to a cascade of deleterious effects throughout the cell, as reactive degradation products drive secondary degradation processes like dissolution of transition metals and decomposition of passivating interfacial species. While in-situ gas evolution measurements conducted by differential electrochemical mass spectrometry (DEMS) allow for the observation and quantification of the degradation processes occurring at the DRX surface, the customized cell configuration with which the technique is conducted is not well suited for capturing the performance decay driven by the interfacial degradation. In particular, a large excess of electrolyte and a large Li metal counter-electrode, both of which are necessary features of DEMS cells, serve to mask the deleterious effects of the interfacial degradation on electrochemical performance. In this work, we reconcile the degradation observed by DEMS with performance decay measured by extended cycling experiments in electrolyte-lean full cells. By comparing DRX outgassing and cycling performance in different voltage windows, we demonstrate a positive correlation between the extent of outgassing and the rate of DRX performance decay during cycling. This result provides a crucial link between the degradation measured by techniques like DEMS and the performance decay measured by cycling experiments, and it allows for the fine-tuning of a cycling voltage window which optimizes the tradeoff between initial performance and long-term stability. Furthermore, this work emphasizes the importance of cell design features, like electrolyte volume and counter-electrode material, and their impact on different electrochemical experiments.
17
Mayer, Matthew T., Alexander Arndt, Laura Carolina Pardo Perez, Chaoqun Ma et Peter Bogdanoff. « Activating New Reaction Pathways in Electrochemical CO2 Conversion Using Pulsing ». ECS Meeting Abstracts MA2024-02, no 62 (22 novembre 2024) : 4183. https://doi.org/10.1149/ma2024-02624183mtgabs.
Texte intégralRésumé :
Electrochemical CO2 conversion can result in a variety of products, often as a mixture, and controlling the product selectivity remains a key challenge. It has been shown that pulsing the electrochemical potential can lead to altered product distributions, influenced by effects on, e.g., transport, double-layer rearrangement, adsorption/desorption, and changes to electrode structure and composition (1). Herein we report our observations using metal electrodes normally selective for the 2-electron formation of CO as major product under steady-state (potentiostatic) conditions, finding that they can produce significant amounts of higher-order products (including methane and ethylene) under the application of pulse potential waveforms. We confirm this is not due to metal impurities in the system, but is significantly affected by phenomena such as surface restructuring and accumulation of liquid products. Furthermore, time-resolved differential electrochemical mass spectrometry (DEMS) measurements reveal distinctly different transient behaviors between the different gaseous products, providing key new mechanistic insight for clarifying the roles of pulsing. (1) Casebolt, R.; Levine, K.; Suntivich, J.; Hanrath, T. Pulse Check: Potential Opportunities in Pulsed Electrochemical CO2 Reduction. Joule 2021, 5 (8), 1987–2026. https://doi.org/10.1016/j.joule.2021.05.014. Figure: Pulsed CO2 reduction on Ag (manuscript pending) -- a) Pulsing waveform with parameter definitions. b) Gas product evolution rates as measured by GC during continuous electrochemical pulsing of a silver foil electrode. c) DEMS study of porous Ag film electrodes, revealing product formation transient behaviors. d) Selectivity dependence on varying the cathodic step potential (Ec) while Ea is fixed. Figure 1
18
Rus, Eric D., Hongsen Wang, Deli Wang et Héctor D. Abruña. « A Mechanistic Differential Electrochemical Mass Spectrometry (DEMS) and in situ Fourier Transform Infrared Investigation of Dimethoxymethane Electro-Oxidation at Platinum ». Journal of Physical Chemistry C 115, no 27 (15 juin 2011) : 13293–302. http://dx.doi.org/10.1021/jp1120405.
Texte intégral
19
He, Meinan, et Mei Cai. « (Invited) A Novel Dems Approach for Studying Gas Evolution in Pouch Cells ». ECS Meeting Abstracts MA2023-02, no 2 (22 décembre 2023) : 218. http://dx.doi.org/10.1149/ma2023-022218mtgabs.
Texte intégralRésumé :
In this study, we designed a novel differential electrochemical mass spectrometry (DEMS) system to in-situ quantify the gas generation in batteries. While a lot of battery gas analyses were carried out by DEMS previously, most of those studies were based on small coin cells or EL cells. The fluid electrolyte and limited amount of active material may make it challenging to quantify the gas generation. The DEMS we designed here can continually sample gas from a small 2.5Ah pouch cell, and it has a similar electrolyte to capacity ratio, 1.8g/Ah, with our production cell. To the best of our knowledge, this is the first DEMS design based on a pouch cell. Moreover, by using flowrate-controlled Ar carrier gas and a reasonable residence time setup, our DEMS design not only can identify volatile electrolyte degradation products throughout battery cycling but also quantify the gaseous species production rates as a function of the state of charge. We found that cell chemistry and operation protocol greatly impact gas product species, the production profile of different gases during cycling, and the total gas quantity. For example, the gas evolution of oxidation products, such as CO2 and CO, is exacerbated by the elevated upper cutoff voltage, while reduction products are only minimally affected. Furthermore, changing the electrolyte SEI former, from EC to FEC, or adding different electrolyte additives can affect the gas product species generation dramatically as well. Therefore, we successfully demonstrated DEMS as a powerful tool to probe the gas evolution behavior in different applications-based batteries, provided valuable data for battery reactivity simulation, and most importantly, provided guidance for electrolyte optimization.
20
Kaufman, Lori A., Dong hun Lee, Tzu-Yang Huang et Bryan D. McCloskey. « The Role of Gas Evolution in Particle Surface Cracking in Nickel-Rich Lithium-Ion Cathode Materials ». ECS Meeting Abstracts MA2022-01, no 2 (7 juillet 2022) : 437. http://dx.doi.org/10.1149/ma2022-012437mtgabs.
Texte intégralRésumé :
Nickel-rich layered oxide cathode materials (LiNixTM(1-x)O2 where x > 0.8) are of great interest because they offer increased capacity compared to current commercial materials while maintaining compatibility with supply chain and production processes already in place. However, recent studies have shown that these materials in their current form are unsuitable for commercial applications due to the accelerated degradation caused by replacing more stable transition metals with the relatively unstable nickel. While various strategies have already been proposed to mitigate this issue, the fundamental degradation mechanism still needs to be better understood to inform the design of the next generation of nickel-rich cathode materials. In this work, differential electrochemical mass spectrometry (DEMS) is combined with titration mass spectrometry (TiMS) to measure gases evolved in a lithium half-cell during cycling as well as surface species which evolve gas upon addition of strong acid to an extracted cathode. Along with qualitative observations of particle cracking by scanning electron microscopy (SEM), these results reveal correlations between particle cracking, electrolyte reactivity, and carbonate oxidation and deposition on the changing cathode surface in nickel-rich cathode materials.
21
Wang, Junkai, Rui Gao et Xiangfeng Liu. « Reversible Conversion between Lithium Superoxide and Lithium Peroxide : A Closed “Lithium–Oxygen” Battery ». Inorganics 11, no 2 (1 février 2023) : 69. http://dx.doi.org/10.3390/inorganics11020069.
Texte intégralRésumé :
Lithium–air batteries have become a desirable research direction in the field of green energy due to their large specific capacity and high energy density. The current research mainly focuses on an open system continuously supplying high-purity oxygen or air. However, factors such as water and CO2 in the open system and liquid electrolytes’ evaporation will decrease battery performance. To improve the practical application of lithium–air batteries, developing a lithium–oxygen battery that does not need a gaseous oxygen supply is desirable. In this study, we designed a closed lithium–oxygen battery model based on the conversion of lithium superoxide and lithium peroxide (LiO2 + e− + Li+ ↔ Li2O2). Herein, the Pd-rGO as a catalyst will produce the LiO2 in the pre-discharge process, and the closed battery can cycle over 57 cycles stably. In addition to in situ Raman spectra, electrochemical quartz crystal microbalance (EQCM) and differential electrochemical mass spectrometry (DEMS) have been applied to explanation the conversion between LiO2 and Li2O2 during the charge–discharge process. This work paves the way to introduce a new closed “lithium–oxygen” battery system for developing large-capacity green energy.
22
Yoo, Ji Mun, Katharina Trapp et Maria R. Lukatskaya. « Electrolyte Engineering for Improved Selectivity of Electrochemical CO2 Reduction ». ECS Meeting Abstracts MA2023-02, no 54 (22 décembre 2023) : 2619. http://dx.doi.org/10.1149/ma2023-02542619mtgabs.
Texte intégralRésumé :
Electrochemical CO2 reduction reaction (eCO2RR) offers a promising solution to produce valuable chemical building blocks especially when coupled with renewable energy sources. However, its practical application faces significant challenges including low production selectivity due to competing hydrogen evolution reactions (HER). As both reactions are highly sensitive to the chemical environment formulated around active sites within electrochemical double layer (EDL), a comprehensive understanding is required on the role of electrolyte components, such as cation, anion, local pH, and water molecules, in tailoring chemical environment and thereby determining selectivity between eCO2RR and HER kinetics on the same catalyst surface. In this context, recent studies have shown that electrolyte engineering can largely control eCO2RR/HER selectivity.[2,3] For instance, different alkali cations have been shown to largely determine CO2 conversion kinetics due to their different hydrated structure within EDL structures.[4] Moreover, an increased cation population within EDL can promote effective eCO2RR over HER even under highly acidic conditions through charge screening effect.[5] Nevertheless, a lack of dynamic information from conventional experimental approaches (e.g. gas chromatography-mass spectrometry) is largely limiting our efforts to comprehensively understand electrolyte engineering effects. To advance our knowledge in electrolyte engineering for high eCO2RR selectivity, it is essential to investigate the functional correlation between electrolyte properties and eCO2RR/HER competition occurring at the electrochemical interface in operando manner.[6,7] In this work, we utilized in situ Differential Electrochemical Mass Spectrometry (DEMS) to monitor the effects of various electrolyte engineering on eCO2RR/HER selectivity in a dynamic manner. Based on the online collection of product molecules and CO2 from Au catalyst surface, in situ DEMS can provide detailed information on both reaction competition between eCO2RR and HER and local CO2 concentration on catalyst surface on electrified catalyst surface. Based on the strength of in situ DEMS analysis, the critical role of electrolyte components will be addressed in terms of eCO2RR/HER kinetics and the local chemical environment. Overall, this work will highlight importance of understanding specific role of electrolyte engineering toward designing efficient eCO2RR systems for carbon-neutral energy technology. [1] A. Wagner, C. D. Sahm, and E. Reisner, Nat. Catal. 2020, 3, 775–786. [2] J. C. Bui, C. Kim, A. J. King, O. Romiluyi, A. Kusoglu, A. Z. Weber, and A. T. Bell, Acc. Chem. Res. 2022, 55, 484-494. [3] G. Marcandalli, M. C. O. Monteiro, A. Goyal, and M. T. M. Koper, Acc. Chem. Res. 2022, 55, 1900-1911. [4] M. C. O. Monteiro, F. Dattila, B. Hagedoorn, R. Garcia-Muelas, N. Lopez, and M. T. M. Koper, Nat. Catal. 2021, 4, 654-662. [5] J. Gu, S. Liu, W. Ni, W. Ren, S. Haussener, and X. Hu, Nat. Catal. 2022, 5, 268-276. [6] A. Goyal, G. Marcandalli, V. A. Mints, and M. T. M. Koper, J. Am. Chem. Soc. 2020, 142, 4154- 4161 [7] E. L. Clark and A. T. Bell, J. Am. Chem. Soc. 2018, 140, 7012-7020.
23
Kumar, Bijandra, Baleeswaraiah Muchharla, Brianna Barbee, Marlon Darby, Kishor Kumar Sadasivuni, Adetayo Adedeji, Abdennaceur Karoui et Mehran Elahi. « Understanding the Role of Underlying Substrates on Hydrogen Evolution Reaction (HER) Catalytic Activity of Atomically Dispersed Pt Atoms ». ECS Meeting Abstracts MA2023-01, no 36 (28 août 2023) : 2106. http://dx.doi.org/10.1149/ma2023-01362106mtgabs.
Texte intégralRésumé :
Electrochemical water splitting is an environmentally friendly way of producing hydrogen, but this process requires highly efficient catalysts. Platinum (Pt) is known the best catalyst for hydrogen evolution reaction (HER) in acidic media, but the scarcity and high cost of Pt limits its applicability in widespread technologies. In this work, we have uncovered the role of underlying substrate on the HER activity of atomically dispersed Pt atoms. A DC magnetron sputtering technique has been utilized to deposit transition metal (Cu, Mo, W, Ti and Ta) thin films as underlying substrates for atomically dispersed and extremely low loading of Pt (< 1.5 at%). As synthesized samples were characterized as electrocatalysts for the HER in both alkali and acidic media. In combination of standard electrochemical experiments (e.g., CV), the differential electrochemical mass spectrometry (DEMS) results show that despite low loading of Pt, the prepared catalysts produce hydrogen at a rate comparable with that of a pristine Pt. Based on the XPS study, the excellent performance is attributed to the modified electronic properties of the Pt atoms due to interaction with underlying substrates. Additionally, the performance of the Pt atoms is significantly governed by the physical properties of underlying substances. Our catalysts also displayed good stability for HER activity and found to be stable after 1000 cycles of continuous operation.
24
Li, Qingyu, Yichao Hou, Jie Yin et Pinxian Xi. « The Evolution of Hexagonal Cobalt Nanosheets for CO2 Electrochemical Reduction Reaction ». Catalysts 13, no 10 (21 octobre 2023) : 1384. http://dx.doi.org/10.3390/catal13101384.
Texte intégralRésumé :
The CO2 electrochemical reduction reaction (CO2RR) is one of the most promising methods to reduce carbon dioxide emissions and store energy. At the same time, the pathways of CO2 reduction reaction are diverse and the products are abundant. Converting carbon dioxide to C2+ products, a critical feedstock, requires a C–C coupling step with the transfer of more than 10 electrons per molecule and, hence, is kinetically sluggish. The production of some key adsorptions is conducive to the formation of C2+ products. In this work, we used in situ techniques to figure out the reason why hexagonal-close-packed (hcp) Co nanosheets (NSs) have high activity in CO2RR to ethanal. According to the in situ Raman spectra, the high local pH environment on the catalyst surface is favorable for CO2RR. The high pH at low potentials not only suppresses the competing hydrogen evolution reaction but also stimulates the production of COCO* intermediate. The isotopic labeling experiment in differential electrochemical mass spectrometry (DEMS) provides a possible sequence of the products. The 13CO is generated when we replace 12CO2 with 13CO2, which identifies the origin of the products. Besides, in situ electrochemical impedance spectroscopy (EIS) shows that the hcp Co at −0.4 V vs. RHE boosts the H2O dissociation and proton transfer, feeding sufficient H* for CO2 to *COOH. In the end, by analyzing the transmission electronic microscopy (TEM), we find that the Co (002) plane may be beneficial to the conversion of CO2 and the adsorption of intermediates.
25
Rastinejad, Justin, Bernardine Lucia Deborah Rinkel et Bryan D. McCloskey. « Quantifying Mixed Redox and Parasitic Processes in Li-Rich Disordered Rocksalt Li-Ion Battery Cathodes ». ECS Meeting Abstracts MA2024-01, no 53 (9 août 2024) : 2796. http://dx.doi.org/10.1149/ma2024-01532796mtgabs.
Texte intégralRésumé :
Li-ion battery demand is expected to increase dramatically as the transportation and power generation sectors become electrified. To address the expense and scarcity of cobalt and nickel used in current layered cathodes, alternative transition metals must be explored. Disordered rocksalt (DRX) cathodes can be fully comprised of affordable, earth-abundant metals such as manganese and titanium and have shown high practical capacity but currently suffer from poor capacity retention and voltage fade [1]. Many researchers have attributed this to O redox, and the subsequent formation of deleterious reactive oxygen species, which can occur in DRX cathodes at states-of-charge as low as 40% [2,3]. Recently, researchers have increased the Mn content in DRX cathodes, with the intent of increasing Mn redox and suppressing O redox [4]. Furthermore, these Mn-rich DRX cathodes undergo a beneficial phase transformation upon electrochemical cycling, increasing capacity and almost eliminating voltage fade [4]. Yet, the redox contributions of Mn and O in these Mn-rich cathodes, especially after this phase transformation, are not understood. Here we decouple capacity contributions from Mn-redox, O-redox, and parasitic processes (e.g. electrolyte decomposition) for Mn-rich DRX using a combination of operando gas measurements and inductively coupled plasma – optimal emission spectrometry (ICP-OES). Mn-rich DRX cathodes were cycled to various states of charge in coin cells and the resulting Mn and O oxidation state were determined via titration mass spectrometry (TiMS) using oxalic acid and triflic acid, respectively. To account for lattice O2 loss, differential electrochemical mass spectrometry (DEMS) was used on select cells. To account for Mn dissolution during cycling, ICP-OES was used to quantify the amount of Mn remaining in the cathode as a function of cycle number. The results of this study provide insight into the various redox processes and interfacial degradation that occurs in DRX cathodes, thereby informing future design to improve high-voltage stability of these promising materials. [1]: Raphaële J. Clément et al 2020 Energy Environ. Sci. 2 345 [2]: Tzu-Yang Huang et al 2023 Adv. Energy Mater. 13 2300241 [3]: Roland Jung et al 2017 J. Electrochem. Soc. 164 A1361 [4]: Zijian Cai et al 2023 Nat. Energy 1
26
Koellisch-Mirbach, Andreas, Pawel Peter Bawol, Inhee Park et Helmut Baltruschat. « (Keynote) Oxygen Reduction and Evolution in Ca2+ Containing DMSO on Atomically Smooth and Rough Pt and Au – Towards a Generalized ORR Mechanism in M2+ Containing DMSO ». ECS Meeting Abstracts MA2022-01, no 49 (7 juillet 2022) : 2063. http://dx.doi.org/10.1149/ma2022-01492063mtgabs.
Texte intégralRésumé :
We demonstrate via cyclic voltammetry, differential electrochemical mass spectrometry (DEMS) and rotating ring disk electrode (RRDE) investigations with variation of the electrode surface roughness and atomically surface structure, that the CaO/CaO2 adsorbate layer formation determines the ORR product distribution. We found that on Pt electrodes peroxide is formed on the clean electrode, whereas superoxide is formed at the adsorbate covered electrode. We furthermore identified four key parameters, which strongly affect the ORR product distribution. The electrode oxide interaction: A strong interaction shifts the product distribution to larger superoxide contribution. The alkaline earth metal oxide interaction: A strong interaction shifts the product distribution to larger peroxide contribution. The electrode surface area: A large electrode surface area delays the completion of the adsorbate layer and increases the peroxide contribution. Electrode surface defects: Defects allow for faster nucleation and thus foster the adsorbate formation, which finally leads to a larger superoxide contribution. Finally, reviewing earlier results of our group we provide a more general mechanism for the oxygen reduction alkaline earth metal cation containing DMSO, for a variety of electrode materials. [1] A. Koellisch-Mirbach, I. Park, M. Hegemann, E. Thome and H. Baltruschat, ChemSusChem, (2021). [2] P.P. Bawol, A. Koellisch-Mirbach, C.J. Bondue, H. Baltruschat and P.H. Reinsberg, ChemSusChem, 14 (2021) 428.
27
Fujihira, Masamichi, et Toshimitsu Noguchi. « A novel differential electrochemical mass spectrometer (DEMS) with a stationary gas-permeable electrode in a rotational flow produced by a rotating rod ». Journal of Electroanalytical Chemistry 347, no 1-2 (avril 1993) : 457–63. http://dx.doi.org/10.1016/0022-0728(93)80111-t.
Texte intégral
28
Subhakumari, Akhila, et Naga Phani B. Aetukuri. « Electrochemical Analysis of Charge Overpotentials in Non-Aqueous Lithium and Sodium Oxygen Batteries ». ECS Meeting Abstracts MA2023-02, no 4 (22 décembre 2023) : 595. http://dx.doi.org/10.1149/ma2023-024595mtgabs.
Texte intégralRésumé :
Aprotic metal-oxygen batteries, especially Li-O2 and Na-O2 batteries, could afford theoretical specific energies of more than 500 Wh/kg. However, while not compromising on rechargeability, the practical realization of the theoretically possible high specific energies has been elusive. A better understanding of the differences and similarities between Li–O2 and Na–O2 battery systems in terms of charge-discharge mechanisms and parasitic chemistry will be meaningful in solving these challenges. Here, we explore the differences between the two systems using a combination of galvanostatic charge-discharge measurements, Differential Electrochemical Mass spectrometry (DEMS), and Potentiostatic Electrochemical Impedance Spectroscopy (PEIS) analysis. The discharge profiles of these battery chemistries are similar in terms of overpotential and have been widely studied. But the origins of the differences in charge overpotentials are not clear. Using in-situ pressure decay measurements during discharge, we calculated the number of electrons/oxygen (e-/O2) to be 2.02 and 1.01 for Li-O2 and Na-O2 cells, respectively. Further, DEMS analysis during charge has shown that the ideal 2 e-/O2 is attained only during the initial phases of charging for Li-O2 cells. However, for Na-O2, the ideal 1 e-/O2 is achieved during a signification portion of the galvanostatic charge step. We corroborate these findings with PEIS and distribution of relaxation times (DRT) analysis to develop a mechanistic view of the processes that lead to poor coulombic and oxygen evolution efficiencies in metal-oxygen cells. Based on DRT analysis, we identify a lower time constant process that is common to both Li-O2 and Na-O2 cells. Interestingly, we observed that voltage polarization is preceded by the observation of this lower time constant peak. In the case of Li-O2 cells, this lower time constant process was observed at the end of discharge and throughout the recharge process, while for the Na-O2 cells, this was only observed after about 70% of recharge. We discuss the possible origins of this low time-constant process and its implications for recharging metal-oxygen batteries. We will also discuss the role of singlet oxygen, if any, in the recharge efficiencies of these two aprotic metal-oxygen batteries. Our results imply that the identification of the origins of this lower time constant process and possible suppression of this process will be key for rechargeable metal-oxygen batteries.
29
Hegemann, M., P. P. Bawol, A. Köllisch-Mirbach et H. Baltruschat. « Mixed Lithium and Sodium Ion Aprotic DMSO Electrolytes for Oxygen Reduction on Au and Pt Studied by DEMS and RRDE ». Electrocatalysis 12, no 5 (15 mai 2021) : 564–78. http://dx.doi.org/10.1007/s12678-021-00669-4.
Texte intégralRésumé :
AbstractIn order to advance the development of metal-air batteries and solve possible problems, it is necessary to gain a fundamental understanding of the underlying reaction mechanisms. In this study we investigate the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER, from species formed during ORR) in Na+ containing dimethyl sulfoxide (DMSO) on poly and single crystalline Pt and Au electrodes. Using a rotating ring disk electrode (RRDE) generator collector setup and additional differential electrochemical mass spectrometry (DEMS), we investigate the ORR mechanism and product distribution. We found that the formation of adsorbed Na2O2, which inhibits further oxygen reduction, is kinetically favored on Pt overadsorption on Au. Peroxide formation occurs to a smaller extent on the single crystal electrodes of Pt than on the polycrystalline surface. Utilizing two different approaches, we were able to calculate the heterogeneous rate constants of the O2/O2− redox couple on Pt and Au and found a higher rate for Pt electrodes compared to Au. We will show that on both electrodes the first electron transfer (formation of superoxide) is the rate-determining step in the reaction mechanism. Small amounts of added Li+ in the electrolyte reduce the reversibility of the O2/O2− redox couples due to faster and more efficient blocking of the electrode by peroxide. Another effect is the positive potential shift of the peroxide formation on both electrodes. The reaction rate of the peroxide formation on the Au electrode increases when increasing the Li+ content in the electrolyte, whereas it remains unaffected on the Pt electrode. However, we can show that the mixed electrolytes promote the activity of peroxide oxidation on the Pt electrode compared to a pure Li+ electrolyte. Overall, we found that the addition of Li+ leads to a Li+-dominated mechanism (ORR onset and product distribution) as soon as the Li+ concentration exceeds the oxygen concentration. Graphical abstract
30
Sawangphruk, Montree, et Krisara Srimanon. « Dry Particle Fusion Assisted Ceramic Coatings for High Nickel Cathode for Scalable 18650 Lithium-Ion Batteries ». ECS Meeting Abstracts MA2022-01, no 2 (7 juillet 2022) : 416. http://dx.doi.org/10.1149/ma2022-012416mtgabs.
Texte intégralRésumé :
Over the last several decades, energy storage has become one of the central tools for facilitating energy transformation from (electro)chemical reactions to electricity. Rechargeable lithium-ion batteries (LIBs) are among the most popular and promising mature technologies for portable electronics, grids, and transportation. The cathode, a working horse, mainly determines the overall capacity among the various components. Off-late layered Li-rich or Ni-rich material plays a vital role, especially Ni-rich LiNixMnyCo1-x-yO2; x ≥ 0.8 (NMC) get significant attention. However, it is unfortunate that such Ni-rich cathode materials encountered severe capacity degradation and poor thermal instability concerning the Ni-concentration. Several strategies have already been proposed to mitigate those issues, including electrolyte additive, cation doping, and coating or surface modification. Among them, the modification of the cathode surface, like core-shell construction, is a practical approach. Herein, a core-shell architecture was achieved by employing the cost-effective dry particle fusion method over Ni-rich (LiNi0.8Mn0.1Co0.1O2 (NMC811), where the nano aluminum oxide was used as a shell material with an average thickness of 150-200 nm. Such NMC@alumina core-shell exhibits excellent cycling stability compared with pristine NMC811. The chemical lithium diffusion coefficient was calculated using galvanostatic (GITT) and the potentio-dynamics process. Additionally, the control of parasitic reaction between the delithiated cathode and electrolyte was analyzed using the in-situ Differential Electrochemical Mass Spectrometry (DEMs) technique, where the onset potential and the amount of gas generated are compared with pristine material.
31
Li, Jingyi, Xiang Li, Charuni M. Gunathunge et Matthias M. Waegele. « Hydrogen bonding steers the product selectivity of electrocatalytic CO reduction ». Proceedings of the National Academy of Sciences 116, no 19 (19 avril 2019) : 9220–29. http://dx.doi.org/10.1073/pnas.1900761116.
Texte intégralRésumé :
The product selectivity of many heterogeneous electrocatalytic processes is profoundly affected by the liquid side of the electrocatalytic interface. The electrocatalytic reduction of CO to hydrocarbons on Cu electrodes is a prototypical example of such a process. However, probing the interactions of surface-bound intermediates with their liquid reaction environment poses a formidable experimental challenge. As a result, the molecular origins of the dependence of the product selectivity on the characteristics of the electrolyte are still poorly understood. Herein, we examined the chemical and electrostatic interactions of surface-adsorbed CO with its liquid reaction environment. Using a series of quaternary alkyl ammonium cations (methyl4N+, ethyl4N+, propyl4N+, and butyl4N+), we systematically tuned the properties of this environment. With differential electrochemical mass spectrometry (DEMS), we show that ethylene is produced in the presence of methyl4N+ and ethyl4N+ cations, whereas this product is not synthesized in propyl4N+- and butyl4N+-containing electrolytes. Surface-enhanced infrared absorption spectroscopy (SEIRAS) reveals that the cations do not block CO adsorption sites and that the cation-dependent interfacial electric field is too small to account for the observed changes in selectivity. However, SEIRAS shows that an intermolecular interaction between surface-adsorbed CO and interfacial water is disrupted in the presence of the two larger cations. This observation suggests that this interaction promotes the hydrogenation of surface-bound CO to ethylene. Our study provides a critical molecular-level insight into how interactions of surface species with the liquid reaction environment control the selectivity of this complex electrocatalytic process.
32
Priamushko, Tatiana, Evanie Franz, Daniel Escalera López, Olaf Brummel, Jörg Libuda, Freddy Kleitz et Serhiy Cherevko. « Assessing the Stability of Co3O4 Under Oxygen Evolution Reaction Conditions at Low and Mild pH ». ECS Meeting Abstracts MA2023-02, no 58 (22 décembre 2023) : 2848. http://dx.doi.org/10.1149/ma2023-02582848mtgabs.
Texte intégralRésumé :
Water and CO2 electrolysis will play a crucial role in converting renewable energy into value-added chemicals and chemical fuels. To successfully employ and expand these technologies globally, ideally, one should develop Earth-abundant, cost-effective catalysts with high activity and stability. The requirements for the catalysts depend on the configuration of the electrolyzer, and the electrolyte used there. However, especially in CO2 electrolysis, the stability of the catalyst in a certain electrolyte does not guarantee its successful use on a long-term scale, as the pH in the electrolyzer may change during long-term experiments due to ion transfer through the membrane.1 The anode materials should, therefore, be stable across a broad pH range and/or in carbonate-rich electrolytes. Although the earth-abundant, non-noble transition metals, and their compounds are highly stable at higher pH, they are less stable than Ir or Pt at low and (near-)neutral pH.2 Interestingly, recent studies have shown that Co-based oxides exhibit promising stability even at low pH.3, 4 However, the nature of this stability as well as the mechanisms of non-noble metal oxides catalyzing OER at low or near-neutral pH, are yet to be discovered. In this work, we analyze the stability of cobalt oxide under various electrochemical conditions at low pH with the use of a scanning flow cell (SFC) coupled with inductively coupled plasma mass spectrometry (ICP-MS) and differential electrochemical mass spectrometry (DEMS). By using these techniques, we can follow the dissolution of Co online and find potential narrow stability windows before and during the oxygen evolution reaction (OER). Benefiting from the obtained results, mitigating strategies for minimizing Co dissolution are proposed and discussed. References: (1) Vass, A.; Kormanyos, A.; Koszo, Z.; Endrodi, B.; Janaky, C. Anode Catalysts in CO2 Electrolysis: Challenges and Untapped Opportunities. ACS Catalysis 2022, 12 (2), 1037-1051. DOI: 10.1021/acscatal.1c04978. (2) Vass, A.; Endrodi, B.; Samu, G. F.; Balog, A.; Kormanyos, A.; Cherevko, S.; Janaky, C. Local Chemical Environment Governs Anode Processes in CO2 Electrolyzers. ACS Energy Letters 2021, 6 (11), 3801-3808. DOI: 10.1021/acsenergylett.1c01937. (3) Cherevko, S. Stabilization of non-noble metal electrocatalysts for acidic oxygen evolution reaction. Current Opinion in Electrochemistry 2023, 38. DOI: ARTN 10121310.1016/j.coelec.2023.101213. (4) Li, A. L.; Kong, S.; Guo, C. X.; Ooka, H.; Adachi, K.; Hashizume, D.; Jiang, Q. K.; Han, H. X.; Xiao, J. P.; Nakamura, R. Enhancing the stability of cobalt spinel oxide towards sustainable oxygen evolution in acid. Nature Catalysis 2022, 5 (2), 109-118. DOI: 10.1038/s41929-021-00732-9.
33
mosen Harzandi, Ahmad, Adel Azaribeni et Mohammad Asadi. « A Rechargeable Solid-State Sodium-Oxygen Battery with Enhanced Energy Efficiency and Cycle Life ». ECS Meeting Abstracts MA2024-01, no 1 (9 août 2024) : 22. http://dx.doi.org/10.1149/ma2024-01122mtgabs.
Texte intégralRésumé :
Sodium-oxygen (Na-O2) batteries offer a promising path for the advancement of high-energy-density inexpensive storage systems to replace current state of the art Li-based batteries owing to the natural abundance and low-cost Na metal. Despite numerous studies to improve the performance of liquid-based electrolyte Na-O2 batteries, this technology suffers from poor cycle life, electrolyte stability issues, and limited choice of cell design as well as growing safety concerns associated with liquid electrolytes. Recently, solid electrolytes received a great attention to substitute traditional liquid electrolytes used in Na-O2 batteries, due to their ability of improving safety and energy density. However, low ionic conductivity and high impedance in contact with the anode and cathode remain as major challenges for the development suitable solid-state electrolyte for Na-O2 batteries. In addressing these challenges, we recently have established a solid-state Na-O2 battery cell that comprises a highly conductive composite polymer-ceramic solid electrolyte with a conductivity of 0.7 mS/cm. This solid electrolyte works in synergy with vanadium phosphide (VP) nanoparticles, serving as oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalysts at the cathode and Na metal anode for more than 500 reversible charge-discharge cycles at a capacity of 1000 mAh/g, achieving a low polarization gap of approximately 20 mV in the first cycle. Various electrochemical and physicochemical characterization techniques, such as Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), differential electrochemical mass spectrometry (DEMS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), were employed to gain insight into the cell chemistry and solid-state electrolyte role in the formation and decomposition of sodium oxides components such as superoxide (NaO2), peroxide (Na2O2). The findings of this study underscore the significance of proper cell component design and possible mechanisms in solid-state Na-O2 battery technologies. This research represents a promising avenue in advancing energy conversion and storage systems, showcasing the potential of solid-state batteries with enhanced safety and performance characteristics.
34
Chen, Sijie, et Weiran Zheng. « Catalyst Deactivation on Transition Metal Oxides during Ammonia Electrooxidation ». ECS Meeting Abstracts MA2024-02, no 56 (22 novembre 2024) : 3763. https://doi.org/10.1149/ma2024-02563763mtgabs.
Texte intégralRésumé :
Electrochemical ammonia oxidation reaction (AOR) offers a sustainable approach for waste ammonia remediation, energy conversion, and valuable product production.[1] Despite the promise of transition metal oxides as effective catalysts, the AOR mechanism on their surface remains elusive, along with factors leading to deactivation, which often involve surface poisoning species formation and site corrosion. Moreover, the AOR potential overlaps with the oxygen evolution reaction (OER), leading to the formation of O2 as a byproduct and an overall decline in energy efficiency. Therefore, it is critical to understand the molecular behavior of ammonia and other species on the oxide surface under reaction conditions. In this work, we systematically investigate the AOR mechanism on NiOOH and CuOOH, emphasizing the influence of OER and dissolved O2, which has been previously largely overlooked. Utilizing three in situ techniques: differential electrochemical mass spectrometry (DEMS) for detecting gaseous intermediates and products, Raman spectroelectrochemistry for monitoring surface transformations, and UV-vis spectroelectrochemistry for observing species within the electrical double layer, we reveal that the formation of NiOOH/CuOOH, the AOR catalytic activity and selectivity, and the deactivation pathway are all significantly modulated by OER and the presence of O2. It is established that AOR on NiOOH is potential-dependent, with N2 production being initiated at potentials coinciding with OER commencement and the generation of NOx species being favored at elevated potentials (Figure 1 left). Moreover, OER competes with the AOR to N2 pathway but promotes the AOR to NOx (N2O, NO, and NO2), which is further elucidated through the protective role of O2 to remove *N poisoning species, mitigating surface deactivation and decreasing charge transfer resistance (Figure 1 right). On CuOOH, however, the O2 can promote NO formation and Cu dissolution from the CuOOH layer, leading to complete deactivation at high potential. Our findings offer an in situ insight into the AOR mechanisms on metal oxides with co-existing OER and provide a critical direction for designing electrocatalysts for environmental applications, particularly for systems where long-term electrolysis is desired. Figure 1. Left: DEMS results during linear sweep voltammetry of NiOOH electrode in Ar/O2-saturated electrolytes (1.0 M KOH + 100 mM NH3). Right: Electrolysis results of NiOOH electrode in Ar/O2 saturated electrolytes (1.0 M KOH + 100 mM NH3) at various potentials. References MacFarlane, D. R.; Cherepanov, P. V.; Choi, J.; Suryanto, B. H. R.; Hodgetts, R. Y.; Bakker, J. M.; Ferrero Vallana, F. M.; Simonov, A. N. Joule, 4 (6), 1186-1205 (2020). Figure 1
35
Lim, Jungwoo, Rory Powell et Laurence J. Hardwick. « Gas Evolution from Sulfide-Based All-Solid-State Batteries ». ECS Meeting Abstracts MA2022-01, no 2 (7 juillet 2022) : 231. http://dx.doi.org/10.1149/ma2022-012231mtgabs.
Texte intégralRésumé :
The demand for high-performance batteries for electrical vehicles (EV) and large-scale energy storage systems have accelerated the development of all-solid-state batteries. Switching from organic liquid electrolyte to solid electrolyte (SE) ensures, not only the high energy density (Wh/L), but also an intrinsic improvement to safety from the removal of flammable solvent in the liquid electrolyte. However, for the development of all-solid-state batteries, still many problems exist toward commercialisation. One challenge is their chemical/electrochemical stability. In case of Li6PS5Cl argyrodite, their electrochemical decomposition was proposed as following reaction. [1] Li6PS5Cl → Li4PS5Cl + 2Li+ + 2e → Li3PS4 + Sx + LiCl → P2Sx + Sx + LiCl + 3Li+ + 3e (1) However, this proposed reaction is bulk electrochemical decomposition of argyrodite. To understand the decomposition in actual cell, layered oxide cathode/argyrodite composite were analysed by in situ Raman microscopy, X-ray photoelectron spectroscopy and Time-of-flight secondary ion mass spectrometry. [2, 3] This research reports actual solid decomposition product formed by active material and solid electrolyte such as POx or (S2)2- compound. Not only for solid decomposition product, but also gaseous decomposition product can be generated from the interface between cathode materials and SE. Previously, much work has demonstrated that O2 and CO2 gases are released from the positive electrode material within the lithium-ion cell. [4] These exothermic surface reactions are important not only for cell swelling in the long-term usage, but also for cell combustion. However, the gas releasing behaviour of positive electrode mixture in all-solid-state batteries are still not well recognised. In this research, we focused on the gas releasing behaviour of all-solid-state batteries. LiNi0.6Mn0.2Co0.2O2 was selected for cathode materials in this research. For the solid electrolyte itself and LiNi0.6Mn0.2Co0.2O2/SE mixture were analysed by Differential Electrochemical Mass Spectroscopy (DEMS). Furthermore, to understand the importance of surface chemistry, air stored LiNi0.6Mn0.2Co0.2O2 and Al2O3 coated LiNi0.6Mn0.2Co0.2O2were prepared. Since air contamination (H2O and CO2) is detrimental for Ni-rich cathode and battery [5], we propose role of surface chemistry in all-solid-state batteries by comparing different LiNi0.6Mn0.2Co0.2O2 composites. As shown in Figure 1, CO2 and O2 gas evolution is observed within an all-solid-state cell as it is charged up to 5 V, with evolution beginning at ca. 4 V highlighting the requirement of stabilising interfaces even when a solid-state electrolyte is used. Figure 1. Comparison of O2 and CO2 gas evolution from (a) Li6PS5Cl and (b) LiNi0.6Mn0.2Co0.2O2/ Li6PS5Cl composite when charged to 5 V vs. Li/Li+. [1] L. Zhou, N. Minafara, W. G. Zeier, L. F. Nazar, Innovative Approaches to Li-Argyrodite Solid Electrolytes for All-Solid-State Lithium Batteries, Acc. Chem. Res., 54, (2021) 2717–2728 [2] Y. Zhou, C. Doerrer, J. Kasemchainan, P. G. Bruce, M. Pasta, L. J. Hardwick, Observation of Interfacial Degradation of Li6PS5Cl against Lithium Metal and LiCoO2 via In Situ Electrochemical Raman Microscopy, Batter. & Supercaps, 3, (2020) 647 –652 [3] F. Walther, R. Koerver, T. Fuchs, S. Ohno, J. Sann, M. Rohnke, W. G. Zeier, J. Janek, Visualization of the Interfacial Decomposition of Composite Cathodes in Argyrodite-Based All-Solid-State Batteries Using Time-of-Flight Secondary-Ion Mass Spectrometry, Chem. Mater, 31, (2019), 3745-3755 [4]S. Sharifi-Asl, J. Lu, K. Amine, R. Shahbazian-Yassar, Oxygen Release Degradation in Li-Ion Battery Cathode Materials: Mechanisms and Mitigating Approaches, Adv. Energy Mater., 9, (2019) 1900551 [5] H. Kim, A. Choi, S. W. Doo, J. Lim, Y. Kim, K. T. Lee, Role of Na+ in the cation disorder of [Li1-xNax] NiO2 as a cathode for lithium-ion batteries, J. Electrochem. Soc., 165, (2018), A201 Figure 1
36
Rastinejad, Justin, et Bryan D. McCloskey. « Understanding High Voltage Electrolyte Reactivity on Cation-Disordered Rock Salt Cathodes ». ECS Meeting Abstracts MA2024-02, no 7 (22 novembre 2024) : 1001. https://doi.org/10.1149/ma2024-0271001mtgabs.
Texte intégralRésumé :
Li-ion battery demand is expected to increase dramatically to meet rapidly increasing energy storage demands. To address the expense and scarcity of cobalt and nickel used in current layered oxide cathodes, alternative cathode materials that rely on earth-abundant transition metals must be explored. Promising such materials are cation-disordered rocksalt (DRX) oxides, particularly those that are comprised of manganese and titanium, along with lithium excess to allow for high reversible capacities (>300 mAh/g). A substantial fraction of extractable lithium capacity in DRX materials occurs at high voltages, creating high energy density, but also leading to deleterious degradation processes. Recent studies have observed reactivity of the DRX surface when cycled to high voltages: >25% of transition metals migrating out of the cathode and continuous evolution of CO2 after 150 cycles [1]. 13C labeling has identified the carbonate electrolyte as the primary source of the CO2 after the first cycle [2]. This reactivity leads to a sharp increase in impedance and rapid capacity fade [1]. However, the exact cause of high voltage reactivity is still not fully understood for the electrolyte – DRX interface. In this study, we quantify the surface reactivity of select electrolyte – DRX systems using operando gas measurements and inductively coupled plasma – optimal emission spectrometry (ICP-OES). Through this method, we can identify what electrolyte and DRX properties have the largest influence on surface reactivity. To monitor surface reactivity of the electrolyte, differential electrochemical mass spectrometry (DEMS) was used to quantify evolution of CO2 and other gaseous products during cycling. To track the surface reactivity of the DRX, ICP-OES was used to quantify transition metal dissolution. We show that ethylene carbonate oxidation is particularly problematic above 4.4 V, and that processes involving the conductive carbon, as well as Mn and O redox are culpable. The results of this study provide insight into the primary causes of capacity fade in DRX-based batteries, informing future designs of the electrolyte, DRX, and other cathode materials. [1]: Matthew J. Crafton et al 2024 J. Electrochem. Soc. 171 020530 [2]: Manuscript in Preparation: Tzu-Yang Huang et al 2024. Chem. Of Mat. (Manuscript ID: cm-2024-007563)
37
Camilo, Mariana R., et Fabio H. B. Lima. « Tin Alloy Nanoparticles for Selective Electrocatalytic Reduction of Carbon Dioxide to Formate ». ECS Meeting Abstracts MA2018-01, no 31 (13 avril 2018) : 1830. http://dx.doi.org/10.1149/ma2018-01/31/1830.
Texte intégralRésumé :
The selective electrocatalytic reduction of CO2 to formate ions or to formic acid is attracting the attention of several researchers. This is mainly because these products can be utilized as hydrogen carriers and as fuels for direct or for indirect fuel cells. In aqueous media, electrocatalysts formed by metals with high hydrogen evolution overpotential, such as Pd, Hg, In, and Sn, are selective for the production of formate (or formic acid, depending on the electrolyte pH). Among these metals, Sn has gained notice because it is abundant and relatively nontoxic. The reasons for the selectivity observed on Sn electrodes are still in debate and has been the subject of recent papers [1,2]. It seems that tin allows the carbon dioxide reduction intermediate to be adsorbed via the oxygen atoms after a proton-couple electron transfer step, so conducting the reaction to the production of formate. In addition, the studies have been discussed the effect of the surface hydroxides, which may enhance the CO2 reduction mainly via two effects: (i) suppressing or decelerating the water electro-reduction and; (ii) allowing a first chemical reaction step with CO2, so producing an adsorbed bicarbonate intermediate (via oxygen atoms), so facilitating the protonation of the carbon atom. In this paper, we will present some results obtained for the CO2 electrochemical reduction on nanostructured tin-alloys, such as Sn-Pd and Sn-Co. The faradaic efficiencies for formate (or formic acid) production were determined via quantitative determination by cyclic voltammetry and experiments of on-line Differential Electrochemical Mass Spectrometry (DEMS) for the formate electro-oxidation after experiments of CO2 electrolysis. It will be discussed the correlation between the nanostructure morphology and Sn oxidation state with the stability and faradaic efficiency for the production of formate (or formic acid) on different electrolytes and pHs. We expect that the obtained results will serve to further understand the main electrocatalyst features that control the selectivity and stability for the CO2 reduction to formate. [1] J.T. Feaster, C. Shi, E.R. Cave, T. Hatsukade, D.N. Abram, K.P. Kuhl, C. Hahn, J.K. Norskov, T.F. Jaramillo, ACS Catal. 7 (2017) 4822 – 4827. [2] J.E. Pander, M.F. Baruch, A.B. Bocarsly, ACS Catal. 2016, 6, 7824−7833. Acknowledgements The authors gratefully acknowledge financial support from FAPESP (2016/13323-0 and 2013/16930-7) and CNPq (306469/20162).
38
Reuter, Lennart, Leonhard J. Reinschlüssel et Hubert Andreas Gasteiger. « Development of a 3-Electrode Setup for the Operando Detection of Parasitic Side Reactions : Exemplified at the Quantification of Released Oxygen ». ECS Meeting Abstracts MA2024-01, no 2 (9 août 2024) : 201. http://dx.doi.org/10.1149/ma2024-012201mtgabs.
Texte intégralRésumé :
The most considerable push to higher energy density Li-ion batteries (LiBs) has been achieved by incremental improvements of the positive electrode cathode active materials (CAM).1 One approach has been to increase the nickel content of layered transition metal oxide CAMs like lithium nickel cobalt aluminum oxide (NCA; LiNixCoyAlzO2, with x+y+z=1) to above 80%, which has already been achieved on a commercial level. While this increase is accommodated by a higher achievable discharge capacity at a given upper cut-off potential, it also reduces the structural stability of the material at high degrees of delithiation (i.e. at high state-of-charge (SOC)).2,3 The structural instability of the CAM is associated with a release of lattice oxygen at high SOC, starting at approximately 80% SOC.2,3 The release of reactive oxygen species is reported to cause a cascade of degradation mechanisms resulting in capacity fade. During this process, the near-surface region of layered transition metal oxide particles is converted into an electrochemically inactive rock-salt phase, which results in the formation of a resistive surface layer.4 Furthermore, the released oxygen can stimulate the chemical oxidation of the typically employed electrolyte solvents, such as ethylene carbonate (EC), resulting in the formation of CO, CO2, and H2O, which in turn hydrolyzes the electrolyte salt.2,5 Consequently, the detection and quantification of released oxygen for different CAMs and cycling conditions is of high interest. Gas quantification methods such as differential electrochemical mass spectrometry (DEMS) and on-line electrochemical mass spectrometry (OEMS) are powerful tools for the qualitative and quantitative measurement of gaseous species such as O2 and CO2.2,6 However, such methods require an expensive mass spectrometer setup and a sophisticated interface between the LiB cell hardware and the mass spectrometer. Thus, in this study, we will present a simplified method that can detect and quantify released oxygen. The method is based on a setup consisting of a dual working electrode (WE) configuration, namely a primary WE with an NCA CAM (LiNi0.80Co0.15Al0.05O2, from BASF TODA Battery Materials LLC, Japan) and an auxiliary WE with only carbon (Vulcan-type carbon, XC-72, Tanaka, Japan), both being coated with a ; a lithium iron phosphate (LFP) electrode coated on aluminum serves as counter electrode (CE). The latter is delithiated to a degree of 90% and capacitively oversized, allowing the NCA working electrode to be cycled against a constant potential (with the LFP potential being at ~3.43 V vs. Li+/Li).8 While charging the NCA working electrode within the desired potential window, the carbon electrode is polarized to a constant potential of 1.21 V vs. the LFP counter electrode corresponding to ~2.20 V vs. Li+/Li. Since oxygen is reduced at that potential, a reductive current is detected once lattice oxygen is being evolved.9 By the precise knowledge of the number of electrons involved in the reduction of oxygen at the carbon electrode, we are able to convert the reductive current into an amount of released oxygen (e.g., in units of moles of oxygen per gram of cathode active material). We apply the developed cell setup to study the oxygen release characteristics of the NCA when being charged to 5.0 V vs. Li+/Li at 0.1 C and 25 °C, and compare these data to the gassing profile analyzed via OEMS. As will be shown, there is a good agreement between integrated and converted reductive current and the amount of detected O2 in the OEMS. References: A. Manthiram, Nat. Commun., 11 (2020). R. Jung, M. Metzger, F. Maglia, C. Stinner, and H. A. Gasteiger, J. Electrochem. Soc., 164, A1361–A1377 (2017). S. Oswald and H. A. Gasteiger, J. Electrochem. Soc., 170, 030506 (2023). F. Friedrich, B. Strehle, A. T. S. Freiberg, K. Kleiner, S. J. Day, C. Erk, M. Piana, and H. A. Gasteiger, J. Electrochem. Soc., 166, A3760–A3774 (2019). M. Stich, M. Göttlinger, M. Kurniawan, U. Schmidt, and A. Bund, J. Phys. Chem. C, 122, 8836–8842 (2018). L. de Biasi, A. Schiele, M. Roca-Ayats, G. Garcia, T. Brezesinski, P. Hartmann, and J. Janek, ChemSusChem, 12, 2240–2250 (2019). N. Tsiouvaras, S. Meini, I. Buchberger, and H. A. Gasteiger, J. Electrochem. Soc., 160, A471–A477 (2013). B. Strehle, K. Kleiner, R. Jung, F. Chesneau, M. Mendez, H. A. Gasteiger, and M. Piana, J. Electrochem. Soc., 164, A400–A406 (2017). Y. C. Lu, H. A. Gasteiger, and Y. Shao-Horn, J. Am. Chem. Soc., 133, 19048–19051 (2011). Acknowledgements: The authors gratefully acknowledge funding from the German Federal Ministry of Education and Research (BMBF) through the project AQua-operaXX (grant number 03XP0328B) and German Federal Ministry of Economic Affairs and Climate Action through the project CAESAR (grant number 03EI3046F).
39
Schmidt, Leon, Kie Hankins, Lars Bläubaum, Michail Gerasimov et Ulrike Krewer. « Identifying Thermal Decomposition Mechanisms of the Solid Electrolyte Interphase with in-Situ Gas Analysis of Lithium-Ion Batteries ». ECS Meeting Abstracts MA2023-02, no 7 (22 décembre 2023) : 949. http://dx.doi.org/10.1149/ma2023-027949mtgabs.
Texte intégralRésumé :
The global shift away from fossil fuels has generated an unprecedented demand for electric vehicles and a steady increase in the prevalence of lithium-ion batteries. Additionally, increases in the energy density of storage technologies has led to a corresponding increase in safety concerns regarding thermal runaway reactions. The components of a lithium-ion battery can self-react when exposed to an external heat source, which can cause a thermal runaway reaction process and large-scale fires of the cell. The initial reactions in this process involve the decomposition of the Solid Electrolyte Interphase (SEI) breakdown and conductive salt. The underlaying mechanisms behind these reactions are unclear; in-depth investigations are needed in order to develop a detailed understanding of the thermal runaway process and guide the development of strategies to mitigate the safety hazards posed by these battery systems. In the past, differential/online electrochemical mass spectrometry (DEMS/OEMS) was utilized to analyze the buildup of the SEI as well as decomposition due to overcharge. Our new methodology of high temperature (HT-)OEMS, with a maximum temperature of 132 °C, can simulate heating events with thermal ramps on an in-situ test cell battery. These measurements reveal information regarding reaction product gases and cell voltage drop during first formation and thermal stress tests, and provide novel insight into the electrochemical and thermodynamic phenomena during thermal abuse of lithium-ion batteries. In this study, we use (HT-)OEMS to investigate the behavior of lithium-ion cells with varied additive concentrations and formation currents. This new methodology allowed us to clearly determine that both of the testing parameters impact the formation gas evolution and thus influence the SEI-composition. Systems with high formation rates, as well as with lower concentrations of additives, exhibited an increase in the fraction of CO product gases, which can be explained with a higher presence of lithium alkoxides in the SEI. Additionally, the evolution of H2, CO2 and POF3 gases were observed at temperatures around 80 °C for cells during the thermal stress test after formation. These results allow us to establish a correlation between the thermal conductive salt decomposition and the formation of the SEI-components Li2CO3 and (CH2OLi)2. The identification of the underlying degradation mechanisms and process correlations via (HT-)OEMS provides a novel and important understanding of the phenomena that give rise to thermal runaway in lithium-ion batteries. This cell chemistry-based insight can be used to guide future prevention-focused safety assessments. Figure 1
40
Bazan, Antony, Gonzalo García, Angélica María Baena-Moncada et Elena Pastor. « Ni Foam-Supported NiMo Catalysts for the HER ». ECS Meeting Abstracts MA2022-01, no 34 (7 juillet 2022) : 1390. http://dx.doi.org/10.1149/ma2022-01341390mtgabs.
Texte intégralRésumé :
In the last years, “green hydrogen” fuel had gained a strong relevance due to its potential as friendly-environment energy source to replace fossil fuels. “Green hydrogen” fuel is obtained from water splitting by electrolysis, which can be powered by renewable energy sources, avoiding the emission of CO2 gas as by-product [1]. Particularly, alkaline water splitting has been, extensively, reported as the most sustainable and low-cost route for “green hydrogen” production. However, either oxygen (OER) or hydrogen evolution (HER) half-reaction can be limited by low-relative abundance of noble metals used as commercial electrocatalysts, such as, the benchmarking IrO2||Pt two-electrode couple of 1.57 V at 10 mA cm-2 [2]. Hence the design of non-noble electrocatalysts has gained relevance due to their remarkable electroactivity and high abundance. Mainly, Ni, Fe, Co and/or Mo - based electrocatalysts showed outstanding performance toward the HER. Indeed, theoretical studies indicated that their metallic surfaces promote the hydrogen electro-adsorption as like-metal hydride [M-H], hydroxide [M-OH] and or oxyhydroxide [MOOH] species [3–5]. Consequently, a controlled charge transfer in a two-step mechanism allows a fast electroreduction of water to the desired “green hydrogen” gas. Herein, we report the synthesis of bimetallic nanostructures, which are produced by thermal-controlled chemical reduction of their precursor salts (NiCl2, Na2MoO4) on the activated nickel foam (NiFA) surface at different highest temperatures (60, 70 and 80 ºC) [4,6]. Therefore, electrocatalysts were labeled as NiMo60/NiFA (60ºC), NiMo70/NiFA (70 ºC) and NiMo80/NiFA (80 ºC). Materials were physicochemical characterized by XRD, SEM, ICP-MS, infrared and Raman spectroscopy, and the HER on the synthesized catalysts in alkaline media was monitored by Differential Electrochemical Mass Spectrometry (DEMS) and in-situ Raman spectroscopy (Fig. a-d). Main results reveal outstanding electrochemical performance toward the HER on the novel nanomaterials, which is mainly influenced by the highest temperature reached at the synthesis procedure. Furthermore, DEMS indicate similar reaction mechanism for the HER at all catalysts and an increment of the catalytic activity rising the temperature at the synthesis stage. References Germscheidt RL, Moreira DEB, Yoshimura RG, Gasbarro NP, Datti E, dos Santos PL, et al. Hydrogen Environmental Benefits Depend on the Way of Production: An Overview of the Main Processes Production and Challenges by 2050. Adv Energy Sustain Res. 2021;2(10):2100093(1-20). Li X, Zhao L, Yu J, Liu X, Zhang X, Liu H, et al. Water Splitting: From Electrode to Green Energy System. Nano-Micro Lett. 2020;12(1):1-29 Abbas MA, Bang JH. Rising Again: Opportunities and Challenges for Platinum-Free Electrocatalysts. Chem Mater. 2015;27(21):7218–7235. Nairan A, Zou P, Liang C, Liu J, Wu D, Liu P, et al. NiMo Solid Solution Nanowire Array Electrodes for Highly Efficient Hydrogen Evolution Reaction. Adv Funct Mater. 2019;29(44):1903747(1–8). Chen G, Wang T, Zhang J, Liu P, Sun H, Zhuang X, et al. Accelerated Hydrogen Evolution Kinetics on NiFe-Layered Double Hydroxide Electrocatalysts by Tailoring Water Dissociation Active Sites. Adv Mater. 2018;30(10):1706279(1-7). Cao J, Li H, Pu J, Zeng S, Liu L, Zhang L, et al. Hierarchical NiMo alloy microtubes on nickel foam as an efficient electrocatalyst for hydrogen evolution reaction. Int J Hydrogen Energy. 2019;44(45):24712–247128. Acknowledgments The Peruvian Fund for Science and Technology (PROCIENCIA) and the Peruvian Minister of Education (MINEDU) by supporting the present work under project 298-2019 FONDECYT and the Doctoral Program with contract 237-2015. The Spanish Ministry of Economy and Competitiveness (MINECO) under project ENE2017-83976 -C2-2-R (FEDER) (co-funded by FEDER). G.G. acknowledges the “Viera y Clavijo” program (ACIISI & ULL), NANOtec, INTech, and Cabildo de Tenerife for laboratory facilities. Authors would like to acknowledge the use of SEGAI—ULL facilities. Figure 1
41
Baltruschat, Helmut. « Differential electrochemical mass spectrometry ». Journal of the American Society for Mass Spectrometry 15, no 12 (décembre 2004) : 1693–706. http://dx.doi.org/10.1016/j.jasms.2004.09.011.
Texte intégral
42
Binder, Markus, Matthias Kuenzel, Thomas Diemant, Zenonas Jusys, Rolf Behm, Joachim Binder, Sandro Stock et al. « A Ternary Additive Mixture for Suppressed Electrolyte Decomposition and Mitigated Gassing in 5V Lnmo‖Graphite Li-Ion Cells ». ECS Meeting Abstracts MA2022-02, no 3 (9 octobre 2022) : 204. http://dx.doi.org/10.1149/ma2022-023204mtgabs.
Texte intégralRésumé :
The cobalt-free spinel LiNi0.5Mn1.5O4 (LNMO) represents a promising candidate for more sustainable high-energy lithium-ion cathodes due to its high operating voltage (4.7 V vs. Li+/Li), low cost and environmental impact, especially when processed in aqueous suspension with water-soluble binders.[1,2] Although the intrinsic properties of the material are already studied extensively and understood quite well, the high working potential still poses challenges for LNMO-comprising lithium-ion battery cells, which need to be addressed before the material can be successfully commercialised. This specifically includes the decomposition of the electrolyte at high potentials and the dissolution of transition metal (TM) ions from the positive electrode and their migration to the negative electrode.[1,3] The latter leads to accelerated electrolyte decomposition also on the anode side and an overall increased gas formation inside the cell.[4] Besides the modification of the material and its surface itself, one of the most promising approaches is the use of electrolyte additives, since this is easy to implement and, therefore, also cost effective. Such additives can be designed to extend the electrochemical stability window, to stabilise the electrode|electrolyte interphases and/or to scavenge harmful species inside the electrolyte.[5–7] The ternary mixture introduced herein decomposes preferentially on both electrodes leading to improved interfacial stability, which is directly reflected in an increased cycling performance of true 5V LNMO‖graphite Li-ion cells – also at elevated temperatures. An in-depth XPS analysis unveiled the growth and composition of a stable interphase layer and showed that this limits the amount of TM deposits on the anode. Finally, in order to demonstrate the beneficial impact also in terms of commercial applicability, the gassing behaviour was investigated qualitatively by differential electrochemical mass spectrometry (DEMS) and quantitatively by exploiting Archimedes’ principle to determine the gas volume formed operando during the cycling of LNMO‖graphite pouch cells. [1] G. Liang, V. K. Peterson, K. W. See, Z. Guo, W. K. Pang, J. Mater. Chem. A 2020, 8, 15373–15398. [2] M. Kuenzel, D. Bresser, T. Diemant, D. V. Carvalho, G. T. Kim, R. J. Behm, S. Passerini, ChemSusChem 2018, 11, 562–573. [3] J. H. Kim, N. P. W. Pieczonka, L. Yang, ChemPhysChem 2014, 15, 1940–1954. [4] B. Michalak, B. B. Berkes, H. Sommer, T. Brezesinski, J. Janek, J. Phys. Chem. C 2017, 121, 211–216. [5] M. Y. Abeywardana, N. Laszczynski, M. Kuenzel, D. Bresser, S. Passerini, B. Lucht, Int. J. Electrochem. 2019, 2019, 1–7. [6] M. S. Milien, H. Beyer, W. Beichel, P. Klose, H. A. Gasteiger, B. L. Lucht, I. Krossing, J. Electrochem. Soc. 2018, 165, A2569–A2576. [7] A. Kazzazi, D. Bresser, M. Kuenzel, M. Hekmatfar, J. Schnaidt, Z. Jusys, T. Diemant, R. J. Behm, M. Copley, K. Maranski, J. Cookson, I. de Meatza, P. Axmann, M. Wohlfahrt-Mehrens, S. Passerini, J. Power Sources 2021, 482, 228975.
43
Wu, Zhenrui, Evan Hansen et Jian Liu. « An in-Depth Study of How Zinc Metal Surface Morphology Determines Aqueous Zinc-Ion Battery Stability ». ECS Meeting Abstracts MA2022-01, no 1 (7 juillet 2022) : 14. http://dx.doi.org/10.1149/ma2022-01114mtgabs.
Texte intégralRésumé :
In order to achieve the net-zero world initiative and combat the climate crisis, a global consensus of marching towards a sustainable energy structure has been built, where developing reliable, affordable, and sustainable energy storage devices, the medium of storing intermittent surplus electricity from clean and inexhaustible renewable energy sources, such as wind power and solar energy, and transferring to the smart electric grid system, is of great significance [1]. Besides lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), the two dominant technologies having been developed substantially in the energy storage industry, researchers started pioneering studies on multivalent-ion systems of Ca [2, 3], Mg [4], Al [5, 6], and Zn [7-9] with competitive advantages, especially the ones as non-flammable economic substitutes, to ease manufacturing burden and enrich practical solutions for widespread application scenarios [10]. Especially, zinc metal with benefits of aqueous compatibility, commensurate capacity (820 mAh/g), and crust abundance, a resurgence of rechargeable zinc-ion batteries (ZIBs) is happening. This battery system with water-based electrolyte chemistries is born with eye-catching benefits of safety and affordability; Zn/MnO2 with an improved energy density of 409 Wh/kg at 1.9 V is considered a promising candidate for grid-scale energy storage [11]. This revolutionary cheap and safe solution empowers the global energy structural transformation and enriches the public’s awareness of sustainable development. However, like most reactive metals, zinc exposed in the air naturally evolves a dense passivation layer of Zn5(CO3)2(OH)6 to discontinue the corrosion by oxygen and humidity, which, in batteries, can passivate the molecular dynamics at the interface between zinc and the electrolyte and demonstrate enormous electron transfer resistance due to the inferior conductivity [12]. Thus, wearing off this passivation layer is considered a facile approach to revitalize the frozen kinetics of zinc ions [13]. Exposing fresh zinc to the electrolyte is also conductive of forming a functional solid-electrolyte interphase (SEI). Studies present that ZnF2-rich SEI plays a pivotal role in elongating the cycling life of zinc symmetric cells by effectively screening zinc from electrolyte solvents and reducing their sequence of side reactions [14]. Additionally, a tactful change of zinc’s surface roughness before electrochemical operations should impact electron distribution, zinc nucleation and growth, and SEI formation. Especially, dendrites are often considered guilty of internal short-circuiting of batteries; similar to lithium, the far-end of zinc dendrites can become dead zinc, whose accumulation brings in issues of electrolyte depletion, anodic capacity loss, internal resistance growth, and cell polarization [15]. In this work, a simple method was developed to change the surface of Zn anode to create more nucleation sites with lowered energy barriers (nucleation over-potentials), thus alleviating their dendrite growth. The cycling programs for zinc symmetric cells are standardized by fixing either the depth of cycling (DOC) or the areal current density in accordance with the constant energy or constant power supply in full batteries. In order to enunciate the battery degradation mechanism and shed light on the gas emission problems, we operate a careful electrochemical analysis cooperated with the differential electrochemical mass spectrometry (DEMS) technique. The preliminary data demonstrate an evident impact of initial zinc surface morphology on sequential zinc plating/stripping profiles and eventual lifespans at serial DOCs and current densities.
44
Zhang, Li, Liang Yin, Weiqun Li, Hou Xu, B. Layla Mehdi et Nuria Tapia Ruiz. « (Digital Presentation) Regulating Anion Redox during Cycling of Spinel LiMn1.5Ni0.5O4 As Cathodes for Lithium Ion Batteries ». ECS Meeting Abstracts MA2022-01, no 2 (7 juillet 2022) : 380. http://dx.doi.org/10.1149/ma2022-012380mtgabs.
Texte intégralRésumé :
In recent years, extensive research has been performed on high energy cathode materials for lithium ion batteries being used in electric vehicles to reduce carbon emissions. Compared to the commercial layered cathode materials, the absence of cobalt in the spinel LiMn1.5Ni0.5O4 (LMNO) makes this material more environmentally friendly and cheaper.1 Spinel LMNO cathodes also reveal attractive gravimetric and volumetric energy densities of 635Whkg−1 and 2820WhL−1, respectively.2 According to the distribution of transition metals (TM) within the cubic crystal structure, spinel LMNO can be categorized into either ordered or disordered. Normally, disordered LMNO materials are produced at temperatures higher than the theoretical oxygen release temperature of spinel LMNO (715 °C).3 The formation of O vacancies is accompanied by some Mn4+ atoms being reduced to Mn3+ to maintain the electroneutrality of spinel LMNO. Ordered LMNO can be obtained through calcination at temperatures lower than 715 °C or post-annealing disordered LMNO materials at 700 °C.4 The reversible extraction and insertion of O atoms accompanied with different distribution of TM during spinel LMNO preparation drive up a hypothesis that the oxygen activity during cycling of spinel LMNO may be affected by the distribution of TM atoms, especially since the operating voltage of spinel LMNO (> 4.7 V) is high enough to trigger oxygen redox in other lithium transition metal oxides.5 To explore the feasibility of oxygen activity during cycling of spinel LMNO, the normal, core-shell and sandwich designed synthesis are performed using special Mn0.75Ni0.25(OH)2 precursors to arrange different distributions of TM atoms in the obtained N-, CS- and SW-LMNO. As shown in Figure 1(a) – (c), the three materials show similar XRD patterns in the pristine state, yet different reflection peaks are observed in the three materials after charging to 4.9 V. The unclear phase transition of SW-LMNO indicates it show stable structure. The three materials also show different CV curves, see Figure 1(d). This indicates the extraction and insertion of Li atoms lead to different redox reactions in the three materials. Besides, differential electrochemical mass spectrometry (DEMS), in-situ transmission electron microscope (TEM) as well as hard and soft X-ray absorption spectroscopy (XAS) measurements are utilized to further investigate the oxygen activity during cycling of spinel LMNO. Reference 1. Li, M. & Lu, J. Cobalt in lithium-ion batteries. Science 367, 979-980 (2020). 2. Hagh, N. M. & Amatucci, G. G. A new solid-state process for synthesis of LiMn1. 5Ni0. 5O4−δ spinel. Journal of Power Sources 195, 5005-5012 (2010). 3. Manthiram, A., Chemelewski, K. & Lee, E.-S. A perspective on the high-voltage LiMn1.5Ni0.5O4 spinel cathode for lithium-ion batteries. Energy & Environmental Science 7, 1339-1350 (2014). 4. Chemelewski, K. R., Shin, D. W., Li, W. & Manthiram, A. Octahedral and truncated high-voltage spinel cathodes: the role of morphology and surface planes in electrochemical properties. Journal of Materials Chemistry A 1, 3347-3354 (2013). 5. Seo, D.-H. et al. The structural and chemical origin of the oxygen redox activity in layered and cation-disordered Li-excess cathode materials. Nature chemistry 8, 692-697 (2016). Figure 1. Operando X-ray diffraction patterns of N- (a), CS- (b) and SW- (c) LiMn1.5Ni0.5O4 in the pristine states and at the charge states of 4.9 V and the corresponding cyclic voltammetry curves of the three materials (d) Figure 1
45
Wasmus, S., S. R. Samms et R. F. Savinell. « Multipurpose Electrochemical Mass Spectrometry : A New Powerful Extension of Differential Electrochemical Mass Spectrometry ». Journal of The Electrochemical Society 142, no 4 (1 avril 1995) : 1183–89. http://dx.doi.org/10.1149/1.2044149.
Texte intégral
46
Abd-El-Latif, A. A., C. J. Bondue, S. Ernst, M. Hegemann, J. K. Kaul, M. Khodayari, E. Mostafa, A. Stefanova et H. Baltruschat. « Insights into electrochemical reactions by differential electrochemical mass spectrometry ». TrAC Trends in Analytical Chemistry 70 (juillet 2015) : 4–13. http://dx.doi.org/10.1016/j.trac.2015.01.015.
Texte intégral
47
Faverge, Theo, Antoine Bonnefont, Marian Chatenet et Christophe Coutanceau. « Electrocatalytic Conversion of Glucose into Hydrogen and Value-Added Compounds on Gold and Nickel Catalysts ». ECS Meeting Abstracts MA2023-02, no 27 (22 décembre 2023) : 1421. http://dx.doi.org/10.1149/ma2023-02271421mtgabs.
Texte intégralRésumé :
Fine chemistry historically relies on the fossil fuel industry, implying oil extraction and refining [1]. The rarefaction of this resource and adverse environmental consequences of its extraction motivate research for alternative sources of chemicals. Low carbon footprint chemicals can be synthesized from nonedible biomass waste [2]; cellulose extracted from biomass can therefore play an important role, being a clean and widely accessible carbon source. One can extract D-Glucose (units that constitute cellulose) from cellulose and obtain numerous chemicals of interest, such as sorbitol [3][4] or gluconic acid [5][6] (gluconate in alkaline media), respectively by selective reduction or oxidation. Searching for high-performance non-enzymatic catalysts to perform such reactions brought us to study the activity and selectivity of gold and nickel in alkaline media. At the anode, results from differential electrochemical mass spectrometry (DEMS) seem to indicate that the glucose oxidation on a gold surface initiates by its dissociative adsorption (dehydrogenation): the dihydrogen (H2) produced likely originates from the formation of metastable H adsorbates (Had) [7] that diffuse onto the surface [8] and recombine into H2. In parallel, the adsorbed glucose oxidizes into value-added products such as gluconic acid, through a mechanism proposed from in situ (Fourier Transform InfraRed spectroscopy, FTIR) and ex situ (products analysis by High Performance Liquid Chromatography, HPLC) observations, and on the evaluation of the number of exchanged electrons using the rotating ring disk electrode (RRDE). Confronting the experimental data to a microkinetics model enables to validate the proposed mechanism and to estimate the kinetics rate constants. At the cathode, the glucose reduction reaction (GRR) into sorbitol competes with the hydrogen evolution reaction (HER). The HER activity of nickel strongly depends on its surface oxidation state [9], which can be tuned to search the best selectivity towards sorbitol. Combining high value-added compounds production with H2 as by-product allows to improve the overall energy efficiency of this electrolysis. [1] P. G. Levi and J. M. Cullen, “Mapping global flows of chemicals: from fossil fuel feedstocks to chemical products,” Environ. Sci. Technol., vol. 52, no. 4, pp. 1725–1734, 2018, doi: 10.1021/acs.est.7b04573. [2] D. Saygin, D. J. Gielen, M. Draeck, E. Worrell, and M. K. Patel, “Assessment of the technical and economic potentials of biomass use for the production of steam, chemicals and polymers,” Renew. Sustain. Energy Rev., vol. 40, pp. 1153–1167, 2014, doi: 10.1016/j.rser.2014.07.114. [3] B. García, J. Moreno, G. Morales, J. A. Melero, and J. Iglesias, “Production of sorbitol via catalytic transfer hydrogenation of glucose,” Appl. Sci., vol. 10, no. 5, 2020, doi: 10.3390/app10051843. [4] X. Guo et al., “Selective hydrogenation of D-glucose to D-sorbitol over Ru/ZSM-5 catalysts,” Chinese J. Catal., vol. 35, no. 5, pp. 733–740, May 2014, doi: 10.1016/S1872-2067(14)60077-2. [5] H. S. Isbell, H. L. Frush, and F. J. Bates, “Manufacture of calcium gluconate by electrolytic oxidation of dextrose,” Ind. Eng. Chem., vol. 24, no. 4, pp. 375–378, 1932, doi: 10.1021/ie50268a003. [6] S. Anastassiadis and I. Morgunov, “Gluconic acid production,” Recent Pat. Biotechnol., vol. 1, no. 2, pp. 167–180, May 2007, doi: 10.2174/187220807780809472. [7] M. M. Jaksic, B. Johansen, and R. Tunold, “Electrochemical behaviour of gold in acidic and alkaline solutions of heavy and regular water,” Int. J. Hydrogen Energy, vol. 18, no. 2, pp. 91–110, Feb. 1993, doi: 10.1016/0360-3199(93)90196-H. [8] J. Cornejo-Romero, A. Solis-Garcia, S. M. Vega-Diaz, and J. C. Fierro-Gonzalez, “Reverse hydrogen spillover during ethanol dehydrogenation on TiO2-supported gold catalysts,” Mol. Catal., vol. 433, pp. 391–402, 2017, doi: 10.1016/j.mcat.2017.02.041. [9] A. G. Oshchepkov et al., “Nanostructured nickel nanoparticles supported on vulcan carbon as a highly active catalyst for the hydrogen oxidation reaction in alkaline media,” J. Power Sources, vol. 402, no. June, pp. 447–452, 2018, doi: 10.1016/j.jpowsour.2018.09.051. Figure 1
48
de Souza, João C. P., Wanderson O. Silva, Fabio H. B. Lima et Frank N. Crespilho. « Enzyme activity evaluation by differential electrochemical mass spectrometry ». Chemical Communications 53, no 60 (2017) : 8400–8402. http://dx.doi.org/10.1039/c7cc03963h.
Texte intégral
49
Song, Yuman, et Hede Gong. « Untargeted Metabolomic Profiling of Fructus Chebulae and Fructus Terminaliae Billericae ». Applied Sciences 14, no 7 (8 avril 2024) : 3123. http://dx.doi.org/10.3390/app14073123.
Texte intégralRésumé :
This study aims to identify the differences in metabolites between Fructus Chebulae (FC) and Fructus Terminaliae Billericae (FTB). Untargeted metabolomics was used to analyze differentially expressed metabolites (DEMs) with ultra-performance liquid chromatography–electrospray ionization–tandem mass spectrometry (UPLC-ESI-MS/MS). A grand total of 558 metabolites were detected, with 155 in positive ion mode and 403 in negative ion mode. Further differential analysis yielded 110 and 87 significantly different metabolites, which were mainly polyphenols, flavonoids, terpenoids, and alkaloids. Analysis of KEGG data showed that differentially expressed metabolites (DEMs) in both positive and negative ion modes were found to be enriched in 5 and 18 metabolic pathways, respectively, with metabolic pathways being the most enriched among them. In sum, this study reveals the differential metabolic profiles of FC and FTB and provides support for their further applications in traditional Chinese medicine.
50
Fujikawa, Keikichi, et Feng Li. « A Review of Differential Electrochemical Mass Spectroscopy Technique Ⅱ.The principle and development of DEMS ». Journal of Electrochemistry 2, journal/vol2/iss4 (28 novembre 1996) : 357–61. http://dx.doi.org/10.61558/2993-074x.3497.
Texte intégral