Literatura académica sobre el tema "Porous composite electrode"
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Artículos de revistas sobre el tema "Porous composite electrode"
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Okafor, Patricia y Jude Iroh. "Electrochemical Properties of Porous Graphene/Polyimide-Nickel Oxide Hybrid Composite Electrode Material". Energies 14, n.º 3 (23 de enero de 2021): 582. http://dx.doi.org/10.3390/en14030582.
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Polyimide-graphene nanosheet composite electrodes are rigid and dense and, therefore, exhibit moderate electrochemical properties. The electrochemical properties of polyimide-graphene nanosheet electrodes were remarkably improved by creating voids in the composite followed by the insertion of nickel oxide into the composites. Nickel oxide particles were electrodeposited onto the porous graphene/poly(amic acid) composite, containing poly (acrylic resin). The hybrid composite was then subjected to thermal treatment at ≥ 300 °C to simultaneously complete imidization and degrade the poly (acrylic resin). Cyclic Voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to study the eletrochemical properties of the composite electrode material. It is shown that remarkable improvement in the electrochemical behavior of the hybrid composite occurred due to the removal of poly(acrylic acid) and the insertion of NiO particles into the polyimide matrix. Fourier Transform Infrared Spectroscopy (FTIR) spectra of the hybrid composites show distinct characteristic peaks for polyimide and NiO in the hybrid composite electrode. Scanning Electron Microscopy, SEM images of the composites, show the presence of NiO aggregates in the composite material. Compared to neat graphene/polyimide composite electrode (GR/PI) composites, the specific capacitance of the hybrid composite electrode increased remarkably by over 250% due to the high interfacial surface area provided by NiO and the concomitant improvement in the electrode–electrolyte interaction.
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Feller, Claudia, Stefan Furche y Markus Eberstein. "Development and characterization of glass matrix composites as porous coating film of a solid state reference electrode". Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2012, CICMT (1 de septiembre de 2012): 000200–000207. http://dx.doi.org/10.4071/cicmt-2012-tp46.
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For protection against leaching of the electrolyte reservoir of a solid state reference electrode a porous covering film was prepared and characterized. The porous covering film is based on a glass matrix composite and fired at 400 °C according to the thick-film-based structure of the reference electrode. Based on stability investigations on low sintering glasses in the range of pH 1.68 to pH 9.18 and in various concentrated potassium chloride solutions, a suitable zinc borate glass was selected. Using this glass and Al2O3 or ZrO2 oxide powders, various glass matrix composites were prepared and their sintering behavior was investigated in dependence on the amount of crystalline fraction up to 45 vol%. The shrinkage was measured by heating microscopy of powder compacts of cylindrical shape. In addition composite films on ZrO2 substrates screen-printed and at 400 °C fired were characterized in terms of their porosity by means of micro structural analysis and electrochemical deposition of copper. According to these investigations, suitable composites were selected as porous covering materials for the reference electrode and were tested therefore. The electrochemical characterization showed that the solid-state reference electrodes with porous covering films have a very good performance compared to conventional reference electrodes.
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Kim, Jisu, Youn-Ji Heo, Jin-Yong Hong y Sung-Kon Kim. "Preparation of Porous Carbon Nanofibers with Tailored Porosity for Electrochemical Capacitor Electrodes". Materials 13, n.º 3 (5 de febrero de 2020): 729. http://dx.doi.org/10.3390/ma13030729.
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Porous carbon electrodes that accumulate charges at the electrode/electrolyte interface have been extensively investigated for use as electrochemical capacitor (EC) electrodes because of their great attributes for driving high-performance energy storage. Here, we report porous carbon nanofibers (p-CNFs) for EC electrodes made by the formation of a composite of monodisperse silica nanoparticles and polyacrylonitrile (PAN), oxidation/carbonization of the composite, and then silica etching. The pore features are controlled by changing the weight ratio of PAN to silica nanoparticles. The electrochemical performances of p-CNF as an electrode are estimated by measuring cyclic voltammetry and galvanostatic charge/discharge. Particularly, the p-CNF electrode shows exceptional areal capacitance (13 mF cm−2 at a current of 0.5 mA cm−2), good rate-retention capability (~98% retention of low-current capacitance), and long-term cycle stability for at least 5000 charge/discharge cycles. Based on the results, we believe that this electrode has potential for use as high-performance EC electrodes.
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Sombatmankhong, Korakot y Adrian C. Fisher. "Development of Porous Polypyrrole Electrode for Fuel Cell Applications". Key Engineering Materials 545 (marzo de 2013): 77–81. http://dx.doi.org/10.4028/www.scientific.net/kem.545.77.
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One method of increasing number of reaction sites was by the introduction of a porous structure into the electrodes to provide a high surface area for catalyst deposition. This work focused on the development of a method for the fabrication of a porous polypyrrole electrode; a mixture of two monomers (i.e. pyrrole and methylene blue) was simultaneously electropolymerised and one of which was selectively removed from the composite film by solvent extraction. The porous polypyrrole had a suitably porous structure whilst maintaining excellent electrical properties. The application of this novel material to miniaturized fuel cells was shown to have improved power density of 2-fold and 3-fold higher than bulk polypyrrole and bare gold electrodes respectively.
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Wang, Qing, Xiao Nan Zhang, Xiao Di Huo, Ren Hui Zhang y Jian Feng Dai. "Study of Nanocrystalline ZnO and Zn2TiO4 Film Electrode with ZnPc Dye and PbS Quantum Dots Composite Sensitization". Advanced Materials Research 287-290 (julio de 2011): 2217–20. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.2217.
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Nanocrystalline ZnO and Zn2TiO4 porous film electrodes were prepared by sol-gel method and spin coating method, and the nanocrystalline porous films were characterized by XRD and SEM. Using ZnPc dye and PbS quantum dots as sensitizers. The nanocrystalline film electrodes of ZnO series and Zn2TiO4 series were prepared separately, and their absorption characteristics observed by UV-vis spectrophotometer. The results showed that ZnPc dye and PbS quantum dots could well sensitize the film electrodes, and the effect of ZnPc dye and PbS quantum dots composite sensitization was optimal. Then, the solar cells were fabricated. In simulation sunlight, the overall photoelectric conversion efficiency by Zn2TiO4/Q-PbS/ZnPc electrode increased by 22%, relative to the ZnO/Q-PbS/ZnPc electrode’s.
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Riyanto, Riyanto, Mohamed Rozali Othman y Jumat Salimon. "ELECTROCHEMICAL OXIDATION OF ETHANOL USING Ni-Co-PVC COMPOSITE ELECTRODE". Indonesian Journal of Chemistry 11, n.º 1 (12 de julio de 2011): 75–84. http://dx.doi.org/10.22146/ijc.21424.
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The morphological characteristics and electrochemical behavior of nickel metal foil (Ni), nickel-polyvinyl chloride (Ni-PVC) and nickel-cobalt-polyvinyl chloride (Ni-Co-PVC) electrodes in alkaline solution has been investigated. The morphological characteristics of the electrode surface were studied using SEM and EDS, while the electrochemical behavior of the electrodes was studied using cyclic voltammetry (CV). It was found that composite electrodes (Ni-PVC and Ni-Co-PVC) have a porous, irregular and rough surface. In situ studies using electrochemical technique using those three electrodes exhibited electrochemical activity for redox system, as well as selectivity in the electrooxidation of ethanol to acetic acid. The studies also found that an electrokinetics and electrocatalytic activity behaviors of the electrodes prepared were Ni metal foil
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Ho, M. Y. y Poi Sim Khiew. "Heat-Treated Fe3O4 - Activated Carbon Nanocomposite for High Performance Electrochemical Capacitor". Advanced Materials Research 894 (febrero de 2014): 349–54. http://dx.doi.org/10.4028/www.scientific.net/amr.894.349.
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The impact of heat treatment temperature on the electrochemical performance of Fe3O4-activated carbon nanocomposite electrodes was investigated using constant current charge-discharge and Electrochemical Impedance Spectroscopy (EIS). An improved capacitive behaviour was observed due to the effect of enhanced ionic and electronic conductivities of the 4 wt% Fe3O4/AC by thermally heating at 200 °C for 6 hours. It was found that the internal resistance of 4 wt% Fe3O4/AC composite electrode calcined at 200 °C for 6 hours is the smallest (2.97 Ω) in comparison to those untreated (4.36 Ω) composite electrodes. The ion mobility inside the porous composite electrodes is favourable at 200 °C, accompanying with the enhanced electronic conductivity of oxide electrode as a result of improved crystallinity. The EIS results and analysis not only have significant impact on the fundamental understanding of the temperature-dependent structural and electrochemical properties of electrode but also provide the insights on the diffusion mechanism of the nanocomposite in neutral Na2SO3electrolyte.
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Kalinina, Elena y Elena Pikalova. "Opportunities, Challenges and Prospects for Electrodeposition of Thin-Film Functional Layers in Solid Oxide Fuel Cell Technology". Materials 14, n.º 19 (26 de septiembre de 2021): 5584. http://dx.doi.org/10.3390/ma14195584.
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Electrolytic deposition (ELD) and electrophoretic deposition (EPD) are relevant methods for creating functional layers of solid oxide fuel cells (SOFCs). This review discusses challenges, new findings and prospects for the implementation of these methods, with the main emphasis placed on the use of the ELD method. Topical issues concerning the formation of highly active SOFC electrodes using ELD, namely, the electrochemical introduction of metal cations into a porous electrode backbone, the formation of composite electrodes, and the electrochemical synthesis of perovskite-like electrode materials are considered. The review presents examples of the ELD formation of the composite electrodes based on porous platinum and silver, which retain high catalytic activity when used in the low-temperature range (400–650 °C). The features of the ELD/EPD co-deposition in the creation of nanostructured electrode layers comprising metal cations, ceramic nanoparticles, and carbon nanotubes, and the use of EPD to create oriented structures are also discussed. A separate subsection is devoted to the electrodeposition of CeO2-based film structures for barrier, protective and catalytic layers using cathodic and anodic ELD, as well as to the main research directions associated with the deposition of the SOFC electrolyte layers using the EPD method.
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Lu, Mi, Yongzhi Mao, Jian Wang, Yongfeng Hu y Jigang Zhou. "Surface heterogeneity in Li0.5CoO2 within a porous composite electrode". Chemical Communications 54, n.º 60 (2018): 8320–23. http://dx.doi.org/10.1039/c8cc03238f.
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Yu, Mei Hui, Hui Min Meng y Ying Xue. "Nano-Mesh Structured Mn-Based Oxide/Conducting Polymer Composite Electrode for Supercapacitor". Materials Science Forum 859 (mayo de 2016): 104–8. http://dx.doi.org/10.4028/www.scientific.net/msf.859.104.
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In this work, modified nano-mesh structured Mn-based oxide electrode material and the supercapacitors are researched. Three types of conducting polymers, i.e. polyaniline (PANI), polypyrrole (PPy) and polythiophene (PTs) are considered to modify Mn-based oxide electrodes. The results of field emission scanning electron microscope show that conducting polymer film can form porous structure on Mn-based oxide electrode, this special structure is beneficial to the improvement of specific surface area, so that the specific capacitance can be increased. The specific capacitance of the supercapacitors assembled by Mn-based oxide/conducting polymer composite electrodes are tested, resulting that the maximum initial specific capacitance is 843 F g-1, cycle life is 105 times. Compared to supercapacitors assembled by general Mn-based oxide electrodes, this Mn-based oxide/conducting polymer material electrode can improve the specific capacitance up to 1.4~1.9 times, and the conductivity and cycle stability can be increased at the same time.
Tesis sobre el tema "Porous composite electrode"
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Bodén, Andreas. "The anode and the electrolyte in the MCFC". Doctoral thesis, KTH, Kemiteknik, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4382.
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A goal of the Swedish government is to increase the usage of renewable fuels and biomass-based fuels. Fuel cells, and especially the MCFC, are useful for these types of fuels. The Swedish market may benefit from the MCFC in two ways: increased efficiency of the biofuels and also utilisation of produced heat in district heating. Most of the commercial MCFC systems today are optimised for use with methane. The possibility to utilise biomass in Sweden makes it important to study how the MCFC may be adapted or optimised for good performance and low degradation with gas produced from biomass or other renewable fuels. This thesis is focused on methods that may be used to investigate and evaluate MCFC electrodes and electrolytes with renewable fuels i.e. CO2-containing gases. The methods and results are both experimental and mathematically modelled. The objectives of this thesis are to better understand how the performance of the anode is dependent on different fuels. Anode kinetics and the water-gas shift reaction have been investigated as well as the possibility to increase cell lifetime by increasing the initial electrolyte amount by having the anode as a reservoir. The effect of segregation of cations in the electrolyte during operation has also been studied. It was found that if the gas composition at the current collector inlet is in equilibrium according to the water gas-shift reaction the gas composition inside the electrode is almost uniform. However, if the gas is not in equilibrium then the concentration gradients inside the current collector have a large effect on the gas composition inside the electrode. The conversion of the gas in the gas flow channels according to the water-gas shift reaction depends on the gas flow rate. For an anode used in a gas mixture of humidified hydrogen and carbon dioxide that are not in equilibrium some solubility of Ni in a (Li/Na)2CO3 mixture was found. To have the anode act as an electrolyte reservoir to prolong cell lifetime the anode pore size should be carefully matched with that of the cathode and a bimodal pore-size distribution for the anode is preferable to have as good performance as possible for as large electrolyte filling degree interval as possible. Modelling results of segregation of cations in the electrolyte during operation indicate that the electrolyte composition changes during operation and that the lithium ions are enriched at the anode for both types of electrolyte used for the MCFC. The electrolyte composition changes are small but might have to be considered in long-time operation. The results from this thesis may be used to better understand how the MCFC may be used for operation with renewable fuels and how electrodes may be designed to prolong cell lifetime.Ett av den svenska regeringens mål är att öka användandet av förnyelsebara bränslen och bränslen från biomassa. Bränsleceller och framförallt MCFC är användbara för dessa typer av bränslen. Den svenska marknaden kan dra fördelar av MCFC på två sätt; ökad bränsleutnyttjandegrad och utnyttjande av producerad värme för fjärrvärme. De flesta kommersiella MCFC-systemen idag är optimerade för användning av metan. Möjligheten att använda biomassa på den svenska marknaden gör det viktigt att studera hur MCFC kan anpassas eller optimeras för bra prestanda och låg degradering för användning med gas från biomassa eller andra förnyelsebara bränslen. Fokus i denna avhandling är på metoder som kan användas för att undersöka och utvärdera MCFC-elektroder och -elektrolyter med förnyelsebara bränslen, dvs. gaser innehållande CO2. Metoderna och resultaten är både experimentella och matematiskt modellerade. Målet med denna avhandling är att bättre förstå hur anodens prestanda beror på användningen av olika bränslen. Anodens kinetik och vattengasskiftreaktionen har studerats liksom möjligheten att förlänga cellens livstid genom att öka den initiala mängden elektrolyt medelst användning av anoden som reservoar. Effekten av segregation av katjoner i elektrolyten under last har också undersökts. Om gassammansättningen är i jämvikt enligt vattengasskiftreaktionen vid inloppet till strömtilledaren kommer gassammansättningen att vara nära uniform inuti elektroden. Om ingående gas inte är i jämvikt kommer stora koncentrationsgradienter uppkomma i strömtilledaren och påverka gassammansättningen i elektroden. Omsättningen med avseende på vattenskiftreaktionen av gasen i flödeskanalen verkar vara beroende av gasens flödeshastighet. För en anod som används i en uppfuktad blandning av vätgas och koldioxid som inte är i jämvikt befanns det att Ni har en viss löslighet i (Li/Na)2CO3. För att kunna använda anoden som reservoar för elektrolyt för att förlänga livstiden för MCFC skall anodens porstorleksfördelning överensstämma med katodens och ha en bimodal porstorleksfördelning för att ge en tillräckligt god prestanda i ett så stort elektrolytfyllnadsgradsintervall som möjligt. Modelleringsresultat för segregering av katjoner i elektrolyten under drift visar att litiumjoner anrikas i anoden för båda typerna av elektrolyt som används i MCFC. Elektrolytkoncentrationsförändringarna är små men kan behövas tas i beaktande vid långa driftstider. Denna avhandlings resultat kan användas för att bättre förstå hur MCFC skall anpassas för drift med förnyelsebara bränslen och hur elektroder kan utformas för att förlänga livstiden.
QC 20100630
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Desprez, Valérie. "Caractérisations, applications et modélisation d'électrodes modifiées par des hydrogels : laponite-oligosilsesquioxanes(-enzyme)". Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE10108.
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Ce memoire est consacre a la caracterisation, aux applications et a la modelisation cinetique d'electrodes modifiees par des hydrogels de laponite expansee par des oligosilsesquioxanes et fonctionnalisee par des especes electrocatalytiques (microparticules de metaux nobles, mediateurs redox, enzymes). Les etudes physico-chimiques et electrochimiques de ce nouveau materiau hybride d'electrode ont mis en evidence l'intercalation des oligosilsesquioxanes et l'existence d'une micro-porosite induite susceptible d'etre conservee en milieu organique. La stabilite des films obtenus ainsi que leur propriete d'echange d'ions offrent de larges potentialites d'application qui ont ete demontrees par plusieurs exemples en electrocatalyse (hydrogenation electrocatalytique) et en electroanalyse (biocapteurs amperometriques). En particulier, l'immobilisation de la polyphenol oxydase (ppox) permet l'elaboration d'un capteur sensible aux composes phenoliques aussi bien en milieux aqueux qu'en milieu organique. Les performances analytiques de ce capteur, tant en sensibilite, temps de reponse qu'en seuil de detection, comptent parmi les meilleures jusqu'ici decrites pour de tels systemes. Enfin, la modelisation cinetique du systeme electroenzymatique catechol/ppox qui met en jeu dans son fonctionnement une regeneration electrochimique du substrat de l'enzyme, a permis de rationaliser le processus d'amplification electroenzymatique responsable des limites de detection extremement basses de ce type de capteur. L'ensemble de ces etudes nous a ainsi permis de proposer une structure mesoporeuse de l'hydrogel enzyme-laponite expansee et de quantifier les modes de transport et d'amplification electroenzymatique.
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Letant, Sonia. "Transfert d'excitation dans les nanocomposites à base de silicium poreux". Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10117.
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Ce travail a ete consacre a l'etude du transfert d'excitation dans les nanocomposites a base de silicium poreux. Le but etait d'etudier le couplage des porteurs photogeneres dans les nanocristaux de silicium avec leur environnement, liquide, solide ou gazeux. Nous presentons ici l'investigation par des methodes de luminescence continue et resolue dans le temps, de trois structures composites : * le silicium poreux dans sa solution acide de formation : un processus de photodissolution des couches poreuses sous lumiere est mis en evidence et caracterise ; dans ce cas, les porteurs fuient physiquement les cristallites pour participer a la reaction photochimique permettant le passage des atomes de silicium dans la solution. * le silicium poreux impregne de colorants laser : il est demontre que les couches poreuses peuvent etre utilisees comme matrice d'accueil passive (excitation directe des molecules) ou active (transfert d'excitation de la matrice vers les molecules via un couplage dipolaire). * le silicium poreux couvert de liaisons si-h : une conversion de l'energie optique en energie vibrationnelle via un couplage dipolaire entre les porteurs et les vibrations de surface a lieu. Le role important de la surface specifique est alors mis en evidence malgre l'origine quantique de l'emission. Il ressort de cette etude que le silicium poreux, malgre sa faible efficacite quantique, est une bonne matrice d'accueil, grace a sa porosite ouverte et a sa grande surface specifique, et qu'il possede les proprietes d'un donneur d'excitation.
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Silveira, Tayla Fernanda Serantoni da [UNESP]. "Materiais porosos e compósitos quimicamente modificados com zircônio (IV) e ácido fosfórico: preparação e aplicações eletroanalíticas". Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/143944.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
O presente trabalho descreve as propriedades espectroscópicas e eletroanalíticas de um composto formado entre o Zr (IV) e ácido fosfórico (ZrP), bem como um espongilito inorganofuncionalizado com Zr (IV) (EZr). Em uma primeira etapa, os materiais foram preparados e caracterizados empregando diferentes técnicas, tais como: Espectroscopia de fotoelétrons excitados por raios-X (XPS), Espectroscopia na região do infravermelho (FTIR), Ressonância magnética nuclear no estado sólido (RMN), Microscopia eletrônica de varredura (MEV), Energia dispersiva de raios-X (EDS), Difração de raios-X (DRX), Análise termogravimétrica (TGA) e Análise de área superficial e porosidade. Em uma segunda etapa, realizou-se um estudo sobre as propriedades eletroquímicas desses materiais após a formação de compósitos com complexos metálicos de hexacianoferrato (ZrPAgH e EZrCuH), utilizando um eletrodo de pasta de grafite. O eletrodo de pasta de grafite contendo ZrPAgH mostrou-se sensível a concentrações de hidrazina e também a compostos sulfidrílicos, tais como: N-acetilcisteína, L-cisteína e L-glutationa. O eletrodo de pasta de grafite contendo EZrCuH foi aplicado na detecção de N-acetilcisteína, L-cisteína, nitrito, piridoxina e hidrazina, com sucesso.
The present work describes the electroanalytical and spectroscopic properties of a compound formed from Zr (IV) and phosphoric acid (ZrP), as well as a inorganofunctionalized spongolite with Zr (IV) (EZr). On a first stage, the materials were prepared and characterized using different techniques such as: X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), Solid state nuclear magnetic resonance (NMR), Scanning electron microscopy (SEM), Energy dispersive X-ray (EDS), X-ray diffraction (XRD), Thermogravimetric analysis (TGA) and Analysis of surface area and porosity. On a second stage, it was carried out a study on the electrochemical properties of these materials after forming composites with metal complexes hexacyanoferrate (ZrPAgH and EZrCuH), using a graphite paste electrode. The graphite paste electrode containing ZrPAgH was sensitive to hydrazine concentrations as well as sulfhydryl compounds, such as: N-acetylcysteine, L-cysteine and L-glutathione. The graphite paste electrode containing EZrCuH was applied to the detection of N-acetylcysteine, L-cysteine, nitrite, pyridoxine and hydrazine, with success.
FAPESP: 2013/08495-9
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Silveira, Tayla Fernanda Serantoni da. "Materiais porosos e compósitos quimicamente modificados com zircônio (IV) e ácido fosfórico : preparação e aplicações eletroanalíticas /". Ilha Solteira, 2016. http://hdl.handle.net/11449/143944.
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Orientador: Devaney Ribeiro do CarmoResumo: O presente trabalho descreve as propriedades espectroscópicas e eletroanalíticas de um composto formado entre o Zr (IV) e ácido fosfórico (ZrP), bem como um espongilito inorganofuncionalizado com Zr (IV) (EZr). Em uma primeira etapa, os materiais foram preparados e caracterizados empregando diferentes técnicas, tais como: Espectroscopia de fotoelétrons excitados por raios-X (XPS), Espectroscopia na região do infravermelho (FTIR), Ressonância magnética nuclear no estado sólido (RMN), Microscopia eletrônica de varredura (MEV), Energia dispersiva de raios-X (EDS), Difração de raios-X (DRX), Análise termogravimétrica (TGA) e Análise de área superficial e porosidade. Em uma segunda etapa, realizou-se um estudo sobre as propriedades eletroquímicas desses materiais após a formação de compósitos com complexos metálicos de hexacianoferrato (ZrPAgH e EZrCuH), utilizando um eletrodo de pasta de grafite. O eletrodo de pasta de grafite contendo ZrPAgH mostrou-se sensível a concentrações de hidrazina e também a compostos sulfidrílicos, tais como: N-acetilcisteína, L-cisteína e L-glutationa. O eletrodo de pasta de grafite contendo EZrCuH foi aplicado na detecção de N-acetilcisteína, L-cisteína, nitrito, piridoxina e hidrazina, com sucesso.
Doutor
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CHANG, CHIA-CHIA y 張家嘉. "Application of Cerium Oxide/Silicon Dioxide/Ordered Porous Carbon Composite Electrode in Supercapacitor". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/59rt3f.
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碩士國立勤益科技大學
化工與材料工程系
107
Supercapacitor is an emerging electric storage device that has been widely applied in various fields, such as consumer electronics, wearable electronics, electric vehicles and micro energy storage components. According to the charge storage mechanism, supercapacitors can be divided into three major types. Electrical double layer capacitor (EDLC) is known for its high specific power density. It generates capacitance by charge carrier adsorption/desorption on the interface between the electrode and the electrolyte. Second, owing to the Faradic reaction, pseudo-capacitors have higher energy density but lower power density than the former one. Third, it is a hybrid capacitor that combines the advantages of both an electric double layer capacitor and a pseudo capacitor. This research is dedicated to the development of ordered mesoporous carbon materials, silicon dioxide and rare earth oxide (CeO2) composites as electrodes for supercapacitors. It is desirable to use the hydrophilic property of Silicon dioxide to help absorb the aqueous electrolyte, thereby increasing the ion transport capacity and achieving the effect of lifting the capacitor, the biggest bright spot of cerium oxide is that during the charge and discharge process, a rapid redox reaction occurs between trivalent cerium and tetravalent cerium, which generates oxygen vacancies and increases conductivity. On the other hand, in recent years, a large number of carbon materials have been used in the research of supercapacitors, and they have achieved outstanding results. This is because they have good stability and conductivity, and this study uses mesoporous carbon materials. CMK-3, a highly regular structure with high specific surface area and adjustable pore characteristics, has also received much attention in the field of electrode materials. For in the ex-situ analysis, Scanning Electron Microscope (SEM), X-ray Diffraction (XRD), Transmission electron microscope (TEM) analysis were adopted to identify the surface morphology, crystal structure, and microstructure of the composite. Nitrogen adsorption-desorption analysis (BET at 77K) was used to analyze the porosity of each specimen. For the in the in-situ test, Chronopotentiometry (CP) was conducted by potentiostat (model: CHI 6273E) to understand the charge and discharge properties. Ragone plot was drawn to further analyze the resistance properties. Based on above analyses, the effect macropores/mespores and the CeO2/HPC ratios on charge-discharge performance were investigated.
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Penki, Tirupathi Rao. "High Capacity Porous Electrode Materials of Li-ion Batteries". Thesis, 2014. http://hdl.handle.net/2005/2907.
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Lithium-ion battery is attractive for various applications because of its high energy density. The performance of Li-ion battery is influenced by several properties of the electrode materials such as particle size, surface area, ionic and electronic conductivity, etc. Porosity is another important property of the electrode material, which influences the performance. Pores can allow the electrolyte to creep inside the particles and also facilitate volume expansion/contraction arising from intercalation/deintercalation of Li+ ions. Additionally, the rate capability and cycle-life can be enhanced. The following porous electrode materials are investigated.
Poorly crystalline porous -MnO2 is synthesized by hydrothermal route from a neutral aqueous solution of KMnO4 at 180 oC and the reaction time of 24 h. On heating, there is a decrease in BET surface area and also a change in morphology from nanopetals to clusters of nanorods. As prepared MnO2 delivers a high discharge specific capacity of 275 mAh g-1 at a specific current of 40 mA g-1 (C/5 rate). Lithium rich manganese oxide (Li2MnO3) is prepared by reverse microemulsion method employing Pluronic acid (P123) as a soft template. It has a well crystalline structure with a broadly distributed mesoporosity but low surface area. However, the sample gains surface area with narrowly distributed mesoporosity and also electrochemical activity after treating in 4 M H2SO4. A discharge capacity of about 160 mAh g-1 is obtained at a discharge current of 30 mA g-1. When the acid-treated sample is heated at 300 °C, the resulting porous sample with a large surface area and dual porosity provides a discharge capacity of 240 mAh g-1 at a discharge current density of 30 mA g-1. Solid solutions of Li2MnO3 and LiMO2 (M=Mn, Ni, Co, Fe and their composites) are more attractive positive electrode materials because of its high capacity >200 mAh g-1.The solid solutions are prepared by microemulsion and polymer template route, which results in porous products. All the solid solution samples exhibit high discharge capacities with high rate capability.
Porous flower-like α-Fe2O3 nanostructures is synthesized by ethylene glycol mediated iron alkoxide as an intermediate and heated at different temperatures from 300 to 700 oC. The α-Fe2O3 samples possess porosity with high surface area and deliver discharge capacity values of 1063, 1168, 1183, 1152 and 968 mAh g-1 at a specific current of 50 mA g-1 when prepared at 300, 400, 500, 600 and 700 oC, respectively. Partially exfoliated and reduced graphene oxide (PE-RGO) is prepared by thermal exfoliation of graphite oxide (GO) under normal air atmosphere at 200-500 oC. Discharge capacity values of 771, 832, 1074 and 823 mAh g -1 are obtained with current density of 30 mA g-1 at 1st cycle for PE-RGO samples prepared at 200, 300, 400 and 500 oC, respectively. The electrochemical performance improves on increasing of exfoliation temperature, which is attributed to an increase in surface area. The high rate capability is attributed to porous nature of the material. Results of these studies are presented and discussed in the thesis.
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Du, Hong-Siang y 杜弘翔. "Electrodeposited Porous MnCoOx / SSM Composite Electrodes for Rechargeable Zn-Air Batteries". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/89643230582251512356.
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碩士南臺科技大學
機械工程系
105
In the rising awareness of environmental protection and the light/thin requirements for 3C products, the disadvantage of primary batteries due to one-time usage to harm the environment makes reusable secondary batteries to become the best choice for storage devices. During discharge of secondary batteries, chemical energy can be converted into electrical energy. During charging, electrical energy will be restored into chemical energy. With the benefit of recycling, secondary batteries are widely used in daily supplies and industries. Traditionally, composite electrodes are prepared using active materials mixed with a conductive agent and a polymer binder into a paste. The paste is then coated onto a substrate as an electrode, with a so-called paste-coating method. There exist some problems for the paste-coating method. For example, the overall capacity and the volumetric capacity of the electrode are significantly sacrificed due to the usage of large- amounts of binder and conductive agent during electrode fabrication. To overcome the disadvantages, we use a binder-free method, named as electrodeposition. Electro-deposition is a low-temperature and low-cost process, which allows controlling the deposition conditions to obtain desirable film thickness without a binder. In this study, mesoporous manganese-cobalt oxides （MnCoOx） spinel films were prepared directly on a conductive stainless steel mesh （SSM） substrate via electrodeposition and an annealing treatment as air/oxygen-diffusion cathode electrode of air battery electrodes. Single potentiostatic electrodeposition （SPE） , were used. For SPE, the potential of 0.6 V was applied for 60 s, 150 s and 300 s and the samples were named as S（MCO/SSM）-1 min, S（MCO/SSM）-2.5 min, and S（MCO/SSM）-5 min, respectively. The electrodeposition mode markedly influenced the surface morphological, textural, and electrochemical properties of the MnCoOx / SSM electrodes. XRD results indicated that the formation of a dual-phase mixture of MnO2 and MnCo2O4 was found. The MnCoOx / SSM electrodes via SPE mode had a best electrochemical performance. The good electrochemical performance and excellent stability of the SPE mode electrodes can be ascribed to its hierarchical structure and high surface area, which facilitates electrolyte ion intercalation and deintercalation at the electrode/electrolyte interface and mitigates volume change during repeated long-term charge/discharge cycling.
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Chen, Fang-Yi y 陳芳儀. "Preparation of Ni-Zn-Co-S/3D porous Ni composite electrodes for supercapacitor applications". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/4s5emx.
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碩士國立中興大學
化學工程學系所
107
In this study, a three-dimensional porous nickel (3D Ni) as the substrate was synthesized via cathodic electrodeposition, followed by a facile two-step strategy that involved the hydrothermal growth of ZnCo-precursor on the 3D Ni and subsequent transformation into Ni-Zn-Co-S through the sulfurization process. The study would include two parts. The first part, Ni-Zn-Co-S was grown directly on the 3D Ni with different deposition times as composite electrodes for supercapacitors. The results indicated that the Ni-Zn-Co-S/3D Ni-6 electrode exhibited the high specific capacitance of 1079.93 F g-1 at the current density of 1 A g-1 due to synergistic effect of the multi-metal and the highly porous architecture. The Ni-Zn-Co-S/3D Ni-6 electrode had good electrochemical properties, and the second part of the study was based on this result. The second part, Ni-Zn-Co-S with different concentrations were grown directly on the 3D Ni-6 as composite electrodes for supercapacitors. The results indicated that the Ni-Zn-Co-S-0.5/3D Ni-6 electrode showed an excellent specific capacitance of 1510.81 F g-1 at the current density of 1 A g-1 with a good cycling stability after 1000 cycles. The remarkable electrochemical performance was attributed to the highly porous and uniform sheet-like architecture, which provided abundant electroactive sites and facilitated transportation of ions/electrons. The results of above analysis demonstrated that Ni-Zn-Co-S-0.5/3D Ni-6 was a promising electrode material for supercapacitors.
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Farhad, Siamak. "Performance Simulation of Planar Solid Oxide Fuel Cells". Thesis, 2011. http://hdl.handle.net/10012/6252.
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The performance of solid oxide fuel cells (SOFCs) at the cell and system levels is studied using computer simulation.
At the cell level, a new model combining the cell micro and macro models is developed. Using this model, the microstructural variables of porous composite electrodes can be linked to the cell performance. In this approach, the electrochemical performance of porous composite electrodes is predicted using a micro-model. In the micro-model, the random-packing sphere method is used to estimate the microstructural properties of porous composite electrodes from the independent microstructural variables. These variables are the electrode porosity, thickness, particle size ratio, and size and volume fraction of electron-conducting particles. Then, the complex interdependency among the multi-component mass transport, electron and ion transports, and the electrochemical and chemical reactions in the microstructure of electrodes is taken into account to predict the electrochemical performance of electrodes. The temperature distribution in the solid structure of the cell and the temperature and species partial pressure distributions in the bulk fuel and air streams are predicted using the cell macro-model. In the macro-model, the energy transport is considered for the cell solid structure and the mass and energy transports are considered for the fuel and air streams.
To demonstrate the application of the cell level model developed, entitled the combined micro- and micro-model, several anode-supported co-flow planar cells with a range of microstructures of porous composite electrodes are simulated. The mean total polarization resistance, the mean total power density, and the temperature distribution in the cells are predicted. The results of this study reveal that there is an optimum value for most of the microstructural variables of the electrodes at which the mean total polarization resistance of the cell is minimized. There is also an optimum value for most of the microstructural variables of the electrodes at which the mean total power density of the cell is maximized. The microstructure of porous composite electrodes also plays a significant role in the mean temperature, the temperature difference between the hottest and coldest spots, and the maximum temperature gradient in the solid structure of the cell. Overall, using the combined micro- and micro-model, an appropriate microstructure for porous composite electrodes to enhance the cell performance can be designed.
At the system level, the full load operation of two SOFC systems is studied. To model these systems, the basic cell model is used for SOFCs at the cell level, the repeated-cell stack model is used for SOFCs at the stack level, and the thermodynamic model is used for the balance of plant components of the system. In addition to these models, a carbon deposition model based on the thermodynamic equilibrium assumption is employed.
For the system level model, the first SOFC system considered is a combined heat and power (CHP) system that operates with biogas fuel. The performance of this system at three different configurations is evaluated. These configurations are different in the fuel processing method to prevent carbon deposition on the anode catalyst. The fuel processing methods considered in these configurations are the anode gas recirculation (AGR), steam reforming (SR), and partial oxidation reformer (POX) methods. The application of this system is studied for operation in a wastewater treatment plant (WWTP) and in single-family detached dwellings. The evaluation of this system for operation in a WWTP indicates that if the entire biogas produced in the WWTP is used in the system with AGR or SR fuel processors, the electric power and heat required to operate the plant can be completely supplied and the extra electric power generated can be sold to the electrical grid. The evaluation of this system for operation in single-family detached dwellings indicates that, depending on the size, location, and building type and design, this system with all configurations studied is suitable to provide the domestic hot water and electric power demands.
The second SOFC system is a novel portable electric power generation system that operates with liquid ammonia fuel. Size, simplicity, and high electrical efficiency are the main advantages of this environmentally friendly system. Using a sensitivity analysis, the effects of the cell voltage at several fuel utilization ratios on the number of cells required for the SOFC stack, system efficiency and voltage, and excess air required for thermal management of the SOFC stack are studied.
Capítulos de libros sobre el tema "Porous composite electrode"
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Atlung, S. "Porous and Composite Electrodes for Solid State Batteries". En Solid State Batteries, 129–61. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-5167-9_11.
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Cheng, Chuan. "Charge-Induced Reversible Bending in Anodic Porous Alumina–Aluminum Composites". En Electro-Chemo-Mechanics of Anodic Porous Alumina Nano-Honeycombs: Self-Ordered Growth and Actuation, 129–41. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-47268-2_8.
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Hai, Chunxi, Hideo Watanabe, Takashi Shirai, Masayoshi Fuji, Feng Wang, Jingjun Liu y Minoru Takahashi. "Chemical Reductive Preparation of Ni Decorated Conductive Porous Alumina Composite and Its Electro-Performance in Alkaline Solution". En Ceramic Transactions Series, 249–54. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2010. http://dx.doi.org/10.1002/9780470917145.ch36.
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Laxman Jadhav, Amar, Sharad Laxman Jadhav y Anamika Vitthal Kadam. "Effect of Different Metals Doped in Nickel Oxide Nanomaterials on Electrochemical Capacitive Performance". En Supercapacitors [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.99326.
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Recently, the various porous nano metal oxides used for the electrochemical energy storage supercapacitor applications. Some researchers focus on the binary as well as ternary metal oxides and more metal oxide complex composite materials used for the supercapacitors. In the review article focused on the effect of different metals doped in a nickel oxide nano material on the electrochemical capacitive performance, discussion on methodologies, charge storage mechanism, latest research articles and prepared nanostructures. Nowadays nickel oxide is developing electrode material for storage of charge due to its higher thermal stability, excellent chemical stability, cost effective materials, higher theoretical values of specific capacitance, naturally rich and environment friendliness material. The various metals doped in NiO and their composite oxides have shown good structural stability, reversible capacity, long cycling stability and have been also studied nano structured electrode materials for electrochemical supercapacitor applications.
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Koshevoi, Veniamin, Anton Belorus, Ilya Pleshanov, Anton Timchenko, Roman Denisenko, Daniyar Sherimov y Ekaterina Vodkailo. "Study of Composite Structures Based on a Porous Silicon Matrix and Nanoparticles Ag/Zno Used as Non-Invasive Highly Sensitive Biosensor Devices". En Composite Materials. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.92850.
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In this work composite structures based on a porous silicon were obtained and studied. Porous matrices were formed by electrochemical etching in aqueous solutions of hydrofluoric acid. Based on the obtained substrates, por-silicon (Si)/silver (Ag) and por-Si/zinc oxide (ZnO) composite structures were formed. These composites were functionalized by various methods (electro (E)-, thermo (T)-, electrothermal exposure) as a result of which the structures were modified. When studying the samples by scanning electron microscopy (SEM), it was concluded that silver nanoparticles actively diffused into the pores under these technological modes of functionalization. The por-Si/Ag and por-Si/ZnO composite structures were also studied using the following methods: infrared (IR) spectroscopy and Raman ultrasoft X-ray emission spectroscopy. Also, the photoluminescent characteristics of the samples were studied. Based on the obtained results, it was concluded that functionalization methods actively change the phase composition of structures and the optical properties of composites.
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Kubade, Pravin R., Amol N. Patil y Hrushikesh B. Kulkarni. "Structure Properties Relationship Studies of Vinyl Ester Hybrid Syntactic Foam". En Handbook of Research on Advancements in Manufacturing, Materials, and Mechanical Engineering, 368–94. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4939-1.ch018.
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Syntactic foam is the porous composite produced by mixing prefabricated hollow spherical particle into the matrix. Syntactic foams are used as energy absorption sandwich core for several applications like marine, automotive, and aerospace. In this work, low density hollow glass microspheres are hybridized with fly ash cenosphere in Bisphenol-A epoxy-based vinyl ester matrix. Hybrid syntactic foams is created with 60% total filler content. Within these hybrid systems internal composition of two fillers were varied in a step of 25 vol% with respect to each other. Hybrid syntactic foams are prepared by the hand lay-up (molding) method. The physical characterization parameter contains density and matrix porosity whereas tensile, quasi-static compression, flexural (3-point bending), Izod impact, and micro Vickers hardness are grouped as mechanical characterization parameters. Scanning electron microscopy was performed on fractured surfaces to examine deformation and fracture mechanisms related with each loading condition.
Actas de conferencias sobre el tema "Porous composite electrode"
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Smerdov, Rostislav S. "Composite Porous Silicon Materials for Emission Electrode Synthesis". En 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech). IEEE, 2019. http://dx.doi.org/10.1109/eexpolytech.2019.8906841.
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Xie, X. y X. Xue. "A Modeling Study of Porous Electrode Property Effects on Solid Oxide Fuel Cell Performance". En ASME 2009 7th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2009. http://dx.doi.org/10.1115/fuelcell2009-85244.
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A two-dimensional isothermal mathematical model is developed for an anode-supported planar solid oxide fuel cell (SOFC). The model takes into account the complex coupling effects of multi-physics processes including mass transfer, charge (ion/electron) transport, and electrochemical reaction. The SOFC multi-physics processes are numerically linked to SOFC global performance such as polarization curve. The model is validated using polarization curve as a metric with the experimental data from open literature. Since triple phase boundary reaction zone may vary from the vicinity of the electrolyte all the way to the entire electrode depending on selected materials and fabrication process, the effects of anode active reaction zone with different volumes are investigated comprehensively for a generic button cell using the developed mathematical model. The tradeoff design between active reaction zone volumes and other design parameters such as porosity and tortuosity of electrodes are also examined. Results show that porous composite electrode properties have very complex effects on SOFC performance. The results may provide a valuable guidance for high performance SOFC design and fabrication.
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P, Shabeeba, Mohammed Shahin Thayyil y M. P. Pillai. "Synthesis and fabrication of porous activated carbon/nano ZnO composite electrode for supercapacitor". En DAE SOLID STATE PHYSICS SYMPOSIUM 2016. Author(s), 2017. http://dx.doi.org/10.1063/1.4980260.
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Yu, Tzyy-Lung Leon, Shih-Hao Liu, Hsiu-Li Lin y Po-Hao Su. "Nafion/PBI Nanofiber Composite Membranes for Fuel Cells Applications". En ASME 2010 8th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2010. http://dx.doi.org/10.1115/fuelcell2010-33025.
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The PBI (poly(benzimidazole)) nano-fiber thin film with thickness of 18–30 μm is prepared by electro-spinning from a 20 wt% PBI/DMAc (N, N′-dimethyl acetamide) solution. The PBI nano-fiber thin film is then treated with a glutaraldehyde liquid for 24h at room temperature to proceed chemical crosslink reaction. The crosslink PBI nano-fiber thin film is then immersed in Nafion solutions to prepare Nafion/PBI nano-fiber composite membranes (thickness 22–34 μm). The morphology of the composite membranes is observed using a scanning electron microscope (SEM). The mechanical properties, conductivity, and unit fuel cell performance of membrane electrode assembly (MEA) of the composite membrane are investigated and compared with those of Nafion-212 membrane (thickness ∼50 μm) and Nafion/porous PTFE (poly(tetrafluoro ethylene)) composite membrane (thickness ∼22 μm). We show the present composite membrane has a similar fuel cell performance to Nafion/PTFE and a better fuel cell performance than Du Pont Nafion-212.
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Recknagle, Kurtis P., Emily M. Ryan y Moe A. Khaleel. "Numerical Modeling of the Distributed Electrochemistry and Performance of Solid Oxide Fuels Cells". En ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64232.
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A cell-level distributed electrochemistry (DEC) modeling tool has been developed to enable predicting trends in solid oxide fuel cell performance by considering the coupled and spatially varying multi-physics that occur within the tri-layer. The approach calculates the distributed electrochemistry within the electrodes, which includes the charge transfer and electric potential fields, ion transport throughout the tri-layer, and gas distributions within the composite and porous electrodes. The thickness of the electrochemically active regions within the electrodes is calculated along with the distributions of charge transfer. The DEC modeling tool can examine the overall SOFC performance based on electrode microstructural parameters, such as particle size, pore size, porosity, electrolyte- and electrode-phase volume fractions, and triple-phase-boundary length. Recent developments in electrode fabrication methods have lead to increased interest in using graded and nano-structured electrodes to improve the electrochemical performance of SOFCs. This paper demonstrates how the DEC modeling tool can be used to help design novel electrode microstructures by optimizing a graded anode for high electrochemical performance.
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Fang, Xudong y Donggang Yao. "An Overview of Solid-Like Electrolytes for Supercapacitors". En ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64069.
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Supercapacitors with an electric double-layer design have attracted great attention in the recent years because they are promising energy storage devices for a number of applications, particularly for portable electronics and electric automobiles. They utilize the interface between the electrode and the electrolyte to store energy, resulting in energy storage devices with high power density but low energy density compared to batteries. To improve the performance and reduce the cost, researchers have made significant progress in increasing energy density, electrode voltage, and cycle life. The increase of the energy density is considered to be achieved mainly by increasing the effective specific interface between the electrodes and the electrolyte. Various electrodes with porous structure have been attempted to increase the specific surface area. The increase of electrode voltage is realized primarily via the change of liquid electrolytes to gel, solid and composite ones. In this overview, they are summarized as solid-like electrolytes. This paper reviews the materials adopted and the processing methods developed for solid-like electrolytes, as well as the general characteristics of supercapacitors employing such electrolytes.
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Baek, Seung-Wook, Joongmyeon Bae y Jung Hyun Kim. "Oxygen Reduction Mechanism at Sm0.5Sr0.5CoO3−δ/Sm0.2Ce0.8O1.9 Composite Cathode for Solid Oxide Fuel Cell". En ASME 2008 6th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2008. http://dx.doi.org/10.1115/fuelcell2008-65059.
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The oxygen reduction mechanism at porous Sm0.5Sr0.5CoO3−δ/Sm0.2Ce0.8O1.9 composite cathode, in which Sm0.5Sr0.5CoO3−δ is a perovskite type mixed ionic and electronic conductor (MIEC), was studied with respect to the oxygen partial pressure and temperature. Symmetric half cells with Sm0.2Ce0.8O1.9 electrolyte were prepared, and cathode behavior was measured by using electrochemical impedance spectroscopy at frequency range of 0.1Hz∼5MHz and temperature range of 400∼900°C. Oxygen partial pressure range for the measurement was from 0.0002 to 1atm. In present research, reaction model based on the empirical equivalent circuit was established. Three elementary reaction steps were considered to describe the oxygen reduction reaction at Sm0.5Sr0.5CoO3−δ/Sm0.2Ce0.8O1.9 composite cathode. Electrode resistances corresponding to the high and low frequency seem to represent the oxygen ion transfer at the interface of electrolyte and gas phase diffusion of oxygen, respectively, from electrochemical impedance analyses as functions of oxygen partial pressure and temperature. The medium frequency process is expected to correspond to the oxygen ion conduction in the bulk cathode from this study.
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Yuan, Jinliang, Masoud Rokni y Bengt Sunde´n. "Gas Flow and Heat Transfer Analysis for an Anode Duct in Reduced Temperature SOFCs". En ASME 2003 1st International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2003. http://dx.doi.org/10.1115/fuelcell2003-1721.
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In this study, a fully three-dimensional calculation method has been further developed to simulate and analyze various processes in a thick anode duct. The composite duct consists of a porous layer, the flow duct and solid current connector. The analysis takes the electrochemical reactions into account. Momentum and heat transport together with gas species equations have been solved by coupled source terms and variable thermo-physical properties (such as density, viscosity, specific heat, etc.) of the fuel gases mixture. The unique fuel cell conditions such as the combined thermal boundary conditions on solid walls, mass transfer (generation and consumption) associated with the electrochemical reaction and gas permeation to / from the porous electrode are applied in the analysis. Results from this study are presented for various governing parameters in order to identify the important factors on the fuel cell performance. It is found that gas species convection has a significant contribution to the gas species transport from / to the active reaction site; consequently characteristics of both gas flow and heat transfer vary widely due to big permeation to the porous layer in the entrance region and species mass concentration related diffusion after a certain distance downstream the inlet.
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Yuan, Jinliang y Bengt Sunde´n. "Effects of Various Reactions on the Gas Flow and Heat Transfer in an Anode Duct of ITSOFCs". En ASME 2005 3rd International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2005. http://dx.doi.org/10.1115/fuelcell2005-74012.
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Recently, there has been considerable interest in the internal reforming reactions of solid oxide fuel cells (SOFCs) using methane or natural gas via. The internal reforming and electrochemical reactions appear in the porous anode layer, and may lead to inhomogeneous temperature and gas species distributions according to the reaction kinetics. A three-dimensional calculation method has been further developed to simulate and analyze the internal reforming and the electrochemical reactions, and the effects on various transport processes in a thick anode duct. In this study, the composite duct consists of a porous anode, fuel flow duct and solid current connector. Momentum, heat transport and gas species equations have been solved by coupled source terms and variable physical properties (density, viscosity, specific heat, etc.) of the fuel gas mixture. The combined thermal boundary conditions on solid walls, mass balances (generation and consumption) associated with the various reactions and gas permeation to/from the porous electrode are applied in the analysis. Simulation results show that the internal reforming and the electrochemical reactions, and operating conditions are significant for fuel gas transport and heat transfer in the anode.
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Ola, Oluwafunmilola y Yanqiu Zhu. "Two-Dimensional WS2/g-C3N4 Layered Heterostructures With Enhanced Pseudocapacitive and Electrocatalytic Properties". En ASME 2020 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/imece2020-23137.
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Abstract In this work, tungsten-based hybrid nanocomposites were grown on interconnected, macroscopic graphitic carbon nitride scaffold after solvothermal treatment followed by sulfidation to attain multifunctional composite electrocatalysts. The physicochemical properties of the obtained samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The tungsten-based composites were tested as electrodes for pseudocapacitors and as electrocatalysts for hydrogen evolution reaction, to take advantage of their porous graphitic carbon nitride features which would be beneficial for optimal ion transport to tungsten-based nanoparticles. These unique physicochemical features endow these composites with excellent electrochemical performances to reach a current density of 10 mA/cm2 for the hydrogen evolution reaction. In addition to demonstrating excellent specific capacitance, these hybrid nanocomposites also possess good stability after 8 hours of testing.
Informes sobre el tema "Porous composite electrode"
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Marschilok, Amy C. Porous Ag/P/C Composite Electrodes: A New Approach for Metal Air Batteries. Fort Belvoir, VA: Defense Technical Information Center, febrero de 2012. http://dx.doi.org/10.21236/ada565200.
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