Dissertations / Theses on the topic 'Additifs de conduction'

Les travaux de cette thèse visent le développement d’un accumulateur au plomb-acide aux propriétés améliorées en combinant l’utilisation d’additifs et la mise en compression des cellules. L’utilisation d’additifs poreux vise à favoriser la diffusion de l’électrolyte au sein de la matière active positive et l’utilisation d’additifs de conductivité tend à optimiser le réseau de conduction des matériaux actifs. Le maintien de la cohésion des matières en cyclage est assuré par la mise en compression des électrodes. Dans cet objectif, un protocole de fabrication d’électrodes positives a été développé au laboratoire. Un comportement de référence a ensuite été définit en déterminant les performances électriques et les caractéristiques des électrodes témoins soumises à des pressions allant de 0 à 1bar. Puis les effets des additifs ont été évalués lors d’applications en compression. Notre but étant également une meilleure compréhension du système plomb-acide et du mode de fonctionnement des additifs, des mécanismes pour expliquer l’évolution texturale des matériaux actifs positifs en compression et l’interaction entre les additifs et l’application d’une pression ont été proposés

La technologie mousse utilisée actuellement pour la conception des électrodes positives des batteries Ni-MH, nécessite l'emploi d'un additif conducteur au cobalt en raison de la mauvaise conductivité électronique de la matière active Ni(OH)2. La recherche de nouveaux composés au cobalt constitue un point clé en vue du développement de ces batteries vers des applications de forte puissance. Dans ce contexte, deux additifs conducteurs potentiels ont été étudiés au cours de ces travaux de thèse. La première partie de l'étude a été focalisée sur des phases spinelle HxLiyCo3-8O4 conductrices, synthètisées par oxydation électrochimique de l'oxyde CoO. Une forte influence du traitement thermique du matériau sur sa conductivité électronique a été mise en évidence. Des analyses par diffraction des rayons X in situ, ATG-SM, RMN et des mesures de conductivités électroniques ont permis de mettre en évidence une redistribution catonique au sein de la structure spinelle, conduisant à une augmentation du rapport atomique Co4+/Co3+ dans le réseau octaédrique [Co2O4], sans variation du degré d'oxydation moyen du cobalt. Il s'ensuit une augmentation de la conductivité elctronique du matériau de trois ordres de grandeur. Le second axe de la thèse concerne l'étude du comportement électrochimique de l'additif Na0,6CoO2. Les réactions échange/insertion des ions alcalins mises en jeu au cours des processus d'oxydation et de réduction de la phase initiale ont été étudiées en détail et un mécanisme a pu être proposé. L'oxyhydroxyde de cobalt hydraté γ, formé par oxydation de Na0,6CoO2 au cours du cyclage, s'est avéré présenter de très bonnes performances lors de tests en batteries. La formation d'une phase interstratifiée intermédiaire, qui possède une cinétique de réduction lente, permet de conserver la stabilité de l'additif à bas potentiel et par conséquent, l'intégralité du réseau conducteur.

Les électrolytes liquides, composés d’un sel dissous dans un solvant, interviennent dans la composition des batteries et font l’objet de nombreuses études afin d’améliorer leurs performances et leur sécurité. Parmi toutes les propriétés essentielles d’un électrolyte, la plus importante est sa conductivité ionique, qui influe sur les performances de la batterie. Pour un sel donné, la conductivité est elle-même principalement déterminée par les propriétés physico-chimiques du solvant comme sa constante diélectrique ou sa viscosité. L’objectif de cette étude est de développer des modèles permettant d’estimer des propriétés d’intérêt des électrolytes liquides, afin d’offrir un gain de temps aux chimistes, qui pourront éliminer les compositions inadéquates du point de vue de telle ou telle propriété. La première partie de cette étude présente une méthode pour estimer la conductivité d’un électrolyte, constitué d’un sel LiPF6 dans un mélange de solvants. Cette méthode s’appuie sur de nouvelles équations, pour estimer les paramètres de l’équation de Casteel-Amis, à partir de propriétés physico-chimiques du mélange de solvants, dont la constante diélectrique. La seconde partie présente a par ailleurs permis de développer une méthode pour estimer la constante diélectrique d’un solvant pur, à partir de sa structure chimique. Cette méthode s’appuie sur de nouveaux modèles additifs qui permettent d’estimer les paramètres de l’équation de Kirkwood-Fröhlich. Parmi ces modèles, deux d’entre eux permettent l’estimation de la densité et de l’indice de réfraction d’un composé liquide à température ambiante. L’ensemble des modèles développés sont utilisables via une interface utilisateur
Liquid electrolytes, composed of a salt dissolved in a solvent, are used in the composition of batteries and are the subject of numerous studies to improve their performance and safety. Of all the essential properties of an electrolyte, the most important is its ionic conductivity, which influences the battery's performance. For a given salt, the conductivity itself is mainly determined by the physico-chemical properties of the solvent such as its dielectric constant or its viscosity. The objective of this study is to develop models to estimate properties of interest of liquid electrolytes, in order to offer time savings to chemists, who will be able to eliminate inadequate compositions from the point of view of such or such property. The first part of this study presents a method to estimate the conductivity of an electrolyte, consisting of a LiPF6 salt in a solvent mixture. This method is based on new equations, to estimate the parameters of the Casteel-Amis equation, based on the physico-chemical properties of the solvent mixture, including the dielectric constant. The second part also presents a method to estimate the dielectric constant of a pure solvent, based on its chemical structure. This method is based on new additive models that estimate the parameters of the Kirkwood-Fröhlich equation. Two of these models estimate the density and refractive index of a liquid compound at room temperature. All the models developed can be used via a user interface

Des poly(liquides ioniques) (PILs) arrangés sous la forme de copolymères statistiques,de nanoparticules à chaine unique ou bien sous la forme de copolymères à blocs autoassemblés ont été employés comme précurseurs de carbènes N-hétérocycliques (NHC)s à des fins de catalyses organiques ou organométalliques. L’introduction d’anions acétate dans des unités PIL dérivés d’imidazolium permet la génération in situ de NHCs actifs en catalyse. Les nanoparticules composées d’une chaine unique polymère repliée sur elle-même (SCNP) ont été spécialement conçues selon deux stratégies impliquant, d’une part, une réaction d’autoquaternisation entre groupements fonctionnels antagonistes portés par la chaine et, d’autre part, une réaction de complexation organométallique à l’aide d’un sel de palladium. Dans lesdeux cas, les chaines polymères ont été obtenues par polymérisation contrôlée (méthode RAFT). Les copolymères à blocs amphiphiles comportant un bloc PIL fonctionnalisé par du palladium ont été synthétisés par polymérisation RAFT et auto-assemblés dans l’eau sous forme de micelles.Un effet de confinement des sites catalytiques a clairement été démontré à travers des réactions de catalyse pour les couplages de Suzuki et de Heck dans l’eau, avec un gain cinétique très net par rapport à des homologues non micellisés, en plus d’une grande facilité de recyclage de ces supports micellaires.Enfin, des copolymères à blocs à base de PIL-benzimidazolium à contre anion bis(trifluoromethane)-sulfonylimide de lithium ont été développés comme agents dopants conducteurs ioniques de matrices structurantes PS-b-PEO. Des mélanges configurés en films minces avec une quantité minimale d’agent dopant ont conduit dans certaines conditions à des valeurs optimales de conductivité ionique grâce à une nano structuration des films à longue distance
Poly(ionic liquid)s (PILs) in the form of random copolymers, single chain nanoparticles(SCNPs), or self assembled block copolymers have been used as N-heterocyclic carbenes(NHCs) precursors for the purpose of organic and organometallic catalysis. Introducing acetate derivative counter anion in imidazolium based PIL units enable in situ generation of catalyticallyactive NHC. SCNPs have been specially designed along two strategies including, firstly, a self quaternization reaction involving two antagonists groups supported on to the polymer chain and,secondly, an organometallic complexation featuring palladium salt. Both polymeric precursors were obtained using RAFT as controlled polymerization method. Amphiphilic block copolymers composed of a PIL block functionalized by palladium have been synthesized by RAFT and self-assembled in water, leading to micellar structures. Confinement effect has been demonstrated through Suzuki and Heck coupling in water showing kinetic gain compared to molecular homologue in addition to an easier recycling method.Finally, PIL-benzimidazolium based block copolymers with lithium bis(trifluoromethane)-sulfonylimide anion have been developed as ionic conductor doping agent for PS-PEO matrix. Thin films blends with minimum doping agent amount led to optimum ionic conductivity owing tolong range order

La tesi se centra en l’ús de nanocomposites conductors elèctricament en la fabricació d’additius. En aquest escenari, dos tipus de nanocomposites estan preparats per utilitzar-los com a matèria primera per a la impressió de nanocomposites conductors elèctricament amb dos tipus diferents de matrius; (1) un polímer termoplàstic i (2) una resina termoestable. Els nanotubs de carboni es van utilitzar com a partícules conductores elèctriques de nanoestructura. Aquestes nanoestructures formen xarxes complexes en una matriu de polímer de manera que el material de la matriu es transforma d’un material aïllant en un material conductor elèctricament. La policaprolactona és un polímer semicristal·lí i es considera material matricial adequat entre la classe de polímers termoplàstics, ja que ofereix unes excel·lents característiques reològiques, de flux i elàstiques. Les cadenes es van imprimir mitjançant una extrusora bio i es va mesurar la conductivitat elèctrica en aquestes cadenes amb l’efecte de la deformació uniaxial. La microstructura canvia sota l’efecte de la deformació uniaxial, provocant una alteració de l’orientació de nanotubs de carboni a la matriu de policaprolactona. Com a conseqüència de la reordenació de nanotubs, les vies conductores es desorganitzen o s’organitzen que poden augmentar o disminuir la conductivitat elèctrica en els nanocomposites. Les radiacions del sincrotró s’utilitzen per sondar aquests canvis en la microestructura. Es van preparar diferents composicions mitjançant nanotubs de carboni i es van estudiar les mostres impreses en termes de conductivitat elèctrica i microestructura mitjançant radiacions de sincrotró. A partir de l’anàlisi, es proposa un model que pugui predir la conductivitat elèctrica sota l’efecte de la deformació uniaxial. En termes de polímers termoestables, s’introdueix un sistema senzill per a la impressió de nanocomposites basats en polímers termoset. En un dels capítols es proporciona un detall complet del sistema d’impressió i de la tinta nanocomposita. Es va preparar tinta de nanocomposites basada en epoxi per contenir nanotubs de carboni com a partícules de farciment amb una petita porció de polímer termoplàstic, policaprolactona. Les mostres impreses estan subjectes al biaix extern que indiquen que són conductores elèctricament. Es van preparar diferents composicions utilitzant resina glicidil bisfenol-A epoxi, trietilenetetramina, policaprolactona, nanotubs de carboni i es destaquen els problemes per obtenir una qualitat d’impressió adequada. Les mostres impreses es van estudiar en termes de conductivitat elèctrica estudiant la conductivitat elèctrica de corrent altern i directe. El sistema material s’explora quant al nivell de reticulació, l’estructura i la morfologia i el comportament tèrmic. Es presenta un model per als nanocomposites mitjançant dades d’impedància obtingudes mitjançant l’espectroscòpia dielèctrica de banda ampla. La impressora s’utilitzarà en un futur per imprimir dispositius funcionals a petita escala, inclosos dispositius d’emmagatzematge d’energia, p. bateries d’estat sòlid, supercondensadors i plaques d’elèctrodes per a aquest tipus de dispositius.
La fabricación aditiva (AM) es un proceso de fabricación de capas sucesivas de material para construir un objeto sólido tridimensional a partir de un modelo digital, a diferencia de las metodologías de fabricación sustractiva. AM ofrece la libertad de diseñar e innovar un producto para que se puedan obtener y revisar piezas complejas si es necesario, en un tiempo reducido en comparación con las tecnologías de fabricación tradicionales. En términos de su utilización total y generalizada, la tecnología tiene aplicaciones limitadas. Por motivos similares, la nanotecnología se considera la fuerza impulsora detrás de una nueva revolución industrial. Tiene la capacidad de incorporar funcionalidades específicas, que se producen debido a la escala nanométrica, a las partes deseadas para dispositivos funcionales como electrodos para dispositivos de almacenamiento de energía. La tesis se centra en el uso de nanocompuestos conductores de electricidad en la fabricación aditiva. En este escenario, dos tipos de nanocompuestos están preparados para usar como materia prima para la impresión de nanocompuestos conductores de electricidad que emplean dos tipos diferentes de material matricial; (1) un polímero termoplástico y (2) una resina termoestable. Los nanotubos de carbono se usaron como partículas de nanoestructura eléctricamente conductoras. Estas nanoestructuras forman redes complejas en una matriz polimérica de manera que el material de la matriz se transforma de un material aislante en un material eléctricamente conductor. La policaprolactona es un polímero semicristalino y se considera un material matriz adecuado entre la clase de polímeros termoplásticos, ya que ofrece excelentes características reológicas, de flujo y elásticas. Los hilos se imprimieron usando una extrusora biológica y se midió la conductividad eléctrica en estos hilos bajo el efecto de la deformación uniaxial. La microestructura cambia bajo el efecto de una deformación uniaxial que conduce a alterar la orientación de los nanotubos de carbono en la matriz de policaprolactona. Como consecuencia de la realineación de los nanotubos, las vías conductoras interrumpen u organizan, lo que puede aumentar o disminuir la conductividad eléctrica en los nanocompuestos. Las radiaciones de sincrotrón se utilizan para sondear tales cambios en la microestructura. Se prepararon diferentes composiciones usando nanotubos de carbono y las muestras impresas se estudiaron en términos de conductividad eléctrica y microestructura usando radiaciones sincrotrónicas. Basado en el análisis, se propone un modelo que puede predecir la conductividad eléctrica bajo el efecto de la deformación uniaxial. En términos de polímeros termoestables, se introduce un sistema simple para la impresión de nanocompuestos termoestables a base de polímeros. El detalle completo del sistema de impresión y la tinta de nanocompuestos se proporciona en uno de los capítulos. La tinta de nanocompuesto a base de epoxi se preparó para contener nanotubos de carbono como partículas de relleno con una pequeña porción de polímero termoplástico, policaprolactona. Las muestras impresas están sujetas al sesgo externo que indica que son eléctricamente conductoras. Se prepararon diferentes composiciones usando resina epoxi de glicidil bisfenol-A, trietilentetramina, policaprolactona, nanotubos de carbono y se resaltan los problemas para adquirir la calidad de impresión adecuada. Las muestras impresas se estudiaron en términos de conductividad eléctrica, estudiando la conductividad eléctrica de corriente alterna y continua. El sistema de materiales se explora en términos del nivel de reticulación, estructura y morfología y comportamiento térmico. Se presenta un modelo para los nanocompuestos utilizando datos de impedancia obtenidos mediante espectroscopía dieléctrica de banda ancha. La impresora se utilizará en el futuro para imprimir dispositivos funcionales a pequeña escala, incluidos dispositivos de almacenamiento de energía.
Additive manufacturing is a process of making successive layers of material to build a three-dimensional solid object from a digital model, as opposed to subtractive manufacturing methodologies. This technology offers the freedom to design and innovation of a product so that complex parts can be obtained and revise if needed, within a small time as compared to traditional manufacturing technologies. In terms of its full utilization and widespread, the technology has limited applications. On similar grounds, nanotechnology is considered as the driving force behind a new industrial revolution. It has the ability to incorporate specific functionalities, occur due to the nanometric scale, to desired parts that offer freedom to design functional devices like electrodes for energy storage devices. The thesis is focusing on the use of electrically conductive nanocomposites into additive manufacturing. In this scenario, two types of nanocomposites are prepared to use as raw material for printing of electrically conductive nanocomposites employing two different types of matrix material; (1) a thermoplastic polymer and (2) a thermoset resin. Carbon nanotubes were used as electrically conductive nanostructure particles. These nanostructures form complex networks into a polymer matrix such that the matrix material transforms from an insulative material into an electrically conductive material. Polycaprolactone is a semicrystalline polymer and it is considered suitable matrix material amongst the class of thermoplastic polymers as it offers excellent rheological, flow and the elastic characteristics. Strands were printed using a bio extruder and electrical conductivity was measured in these strands under the effect of uniaxial deformation. The microstructure changes under the effect of uniaxial deformation leading to alter the orientation of carbon nanotubes in the polycaprolactone matrix. As a consequence of realignment of nanotubes, conductive pathways either disrupt or organize which can increase or decrease an electrical conductivity in the nanocomposites. Synchrotron radiations are used to probe such changes in the microstructure. Two different compositions were prepared using carbon nanotubes and the printed samples are studied in terms of electrical conductivity and microstructure using synchrotron radiations. Based on the analysis, a model is proposed that can predict the orientation of carbon nanotubes under the effect of uniaxial deformation. In terms of thermoset polymers, a simple system is introduced for the printing of thermoset polymer (epoxy) based nanocomposites. Complete detail of the printing system is provided in one of the chapters. Epoxy-based nanocomposite ink was prepared to contain carbon nanotubes as filler particles with a small portion of thermoplastic polymer, polycaprolactone. The printed samples are subject to the external bias which indicate that these are electrically conductive. A complete methodology was provided for the preparation of nanocomposite ink. Different compositions were prepared using glycidyl bisphenol-A epoxy resin, triethylenetetramine, polycaprolactone, carbon nanotubes and issues are highlighted to acquire appropriate print quality. The printed samples were studied in terms of electrical conductivity studying alternating and direct current electrical conductivity. The material system is explored in terms of the level of crosslinking, structure and morphology and thermal behaviour. A model is presented for the nanocomposites using impedance data obtained through broadband dielectric spectroscopy. The printer will be used in future to print small scale functional devices including energy storage devices e.g. solid-state batteries, supercapacitors and electrode plates for such kind of devices.
Universitat Autònoma de Barcelona. Programa de Doctorat en Ciència de Materials

The growing demand in portable and compact consumer devices and appliances has resulted in the need for the miniaturisation of electronic components. These miniaturised electronic components are sensitive and susceptible to damage by voltages as low as 20V. Electrically conductive styrenic thermoplastics are widely used in electronic packaging applications to protect these sensitive electronic components against electro-static discharge (ESD) during manufacturing, assembly, storage and shipping. Such ESD applications often require the optimal volume resistance range of ≥ 1.0x105 to < 1.0x108 Ω. The best known method to render styrenic thermoplastics conductive is by the incorporation of conductive fillers, such as carbon black but the main limitation is the difficulty in controlling the conductivity level due to the steep percolation curve. Thus the aim of this research is to develop electrically conductive styrenic thermoplastics by blending several styrenic resins with polymeric conductive additives to achieve optimal volume resistance range for ESD applications with the ease in controlling the conductivity level.

In this study, bulk conductivity of commercial base paper impregnated with different ionic liquids blends and additives, through bench coating was investigated. Bulk conductivity of base paper, ion conductive paper and surface sized ion conductive papers with and without the influence of calendering were evaluated at different concentrations of ionic liquids using at resistivity cell and four point probe technique. It was shown that bulk conductivity of base paper was increased by increasing the amount of ionic liquids. Nano fibril cellulose also showed positive influence on the bulk conductivity of coated papers. By increasing the line load in the calendering machine, a positive influence on the bulk conductivity was observed. The tensile index of all the coated papers was lower than that of the base paper.

Conductive carbon additives are important constituents of the current state-of-the-art Li-ion battery cathodes, as the traditional active cathode materials are characterized by too low electronic conductivities. In high-voltage Li-ion batteries, these additives are subject for anion intercalation and electrolyte oxidation, which might cause changes in the conductive carbon network in the cathode, and hence the overall cycling performance of the electrode. This thesis has focused on study the stability of three types of carbon additives operating at high voltages. Materials included were two conventional types of conductive additives, graphite, KS6, and carbon black, Super P Li, both provided from TIMCAL. In addition, a multilayer graphene powder, Graphene AO-2, provided from Graphene Supermarket has been investigated. The powder properties, size, shape and structure, were studied in a scanning electron microscope and by powder X-ray diffraction. Electrodes from these materials were cycled galvanostatically and with cyclic voltammetry to reveal their high-voltage behaviour, with respect to the two above mentioned electrochemical processes. More detailed investigations of anion intercalation in KS6 and Graphene AO-2 were conducted by in situ X-ray diffraction measurements and scanning electron microscopy. For cycling in 30:70 vol% EC/DMC 1 M LiPF6 to a voltage of 4.7 V vs. Li+/Li, the results showed that Super P Li can be considered as the most stable conductive additive. At 4.7 V vs. Li+/Li, both KS6 and Graphene AO-2 are electrochemically active, while Graphene AO-2 displays a more reversible behavior, and are more stable than KS6. For even higher operation potential, 5.0 V vs. Li+/Li, Graphene AO-2 showed the least stable behavior of the three materials, due to large degree of electrolyte oxidation, unstable anion intercalation upon continuous cycling, and the suggestions of structural degradation of the electrode. However, a small increase in the electrolyte stability window was shown with Graphene AO-2 when changing to a more viscous electrolyte (1:1 vol% EC/DMC 1 M LiPF6) or adding an anion receptor (tris(hexafluoroisopropyl)borate) to the electrolyte. The anion intercalation in KS6 was observed to form staged phases, starting at 4.83 V vs. Li+/Li. The electrode structure was suggested to be affected in a smaller extent compared to Graphene AO-2. In addition, less electrolyte was oxidized at the KS6 electrode surface, compared to the two other materials. However, the film formed on the Super P Li electrodes did not seem to affect the carbon negatively, because stable anion intercalation was observed upon continuous cycling. Indicating that Super P Li was not strongly affected by the intercalation process.

Inorganic salts are very promising as high-temperature heat transfer fluids and thermal storage media in solar thermal power production. The dual-tank molten salt storage system, for example, has been demonstrated to be effective for continuous operation in solar power tower plants. In this particular storage regime, however, much of the thermal storage potential of the salts is ignored. Most inorganic salts are characterized by high heats of fusion, so their use as phase-change materials (PCMs) allows for substantially higher energy storage density than their use as sensible heat storage alone. For instance, use of molten sodium-potassium eutectic salt over a temperature range of 260 to 560°C (the approximate operating parameters of a proposed utility-scale storage system) allows for a volumetric energy storage density of 212 kWhth/m3, whereas the use of pure sodium nitrate (T_m = 307°C) over the same temperature range (utilizing both sensible and latent heat) yields a storage density of 347 kWhth/m3. The main downside to these media is their relatively low thermal conductivity (typically on the order of 1 W/m-K). While low conductivity is not as much an issue with heat transfer fluids, which, owing to convective heat transfer, are not as reliant on conduction as a heat transfer mode, it can become important for PCM storage strategies, in which transient charging behavior will necessarily involve heating the solid-phase material up to and through the process of melting. This investigation seeks to develop new methods of improving heat transfer in inorganic salt latent heat thermal energy storage (TES) media, such as sodium / potassium nitrates and chlorides. These methods include two basic strategies: first, inclusion of conductivity-enhancing additives, and second, incorporation of infrared absorptive additives in otherwise transparent media. Also, in the process, a group of chloride based salts for use as sensible storage media and/or heat transfer fluids has been developed, based on relevant cost and thermophysical properties data. For direct conductivity enhancement, the idea is simple: a PCM with low conductivity can be enhanced by incorporation of nanoparticulate additives at low concentration (~5 wt %). This concept has been explored extensively with lower temperature heat transfer fluids such as water, ethylene glycol, etc. (e.g., nanofluids), as well as with many lower temperature PCMs, such as paraffin wax. Extension of the concept to high temperature inorganic salt thermal storage media brings new challenges—most importantly, material compatibility. Also, maintenance of the additive distribution can be more difficult. Promising results were obtained in both these regards with nitrate salt systems. The second heat transfer enhancement strategy examined here is more novel in principle: increasing the infrared absorption of a semitransparent salt PCM (e.g., NaCl) with a suitable additive can theoretically enhance radiative heat transfer (for sufficiently high temperatures), thereby compensating for low thermal conductivity. Here again, material compatibility and maintenance of additive dispersion become the focus, but in very different ways, owing to the higher temperatures of application (>600°C) and the much lower concentration of additives required (~0.5 wt %). Promising results have been obtained in this case, as well, in terms of demonstrably greater infrared absorptance with inclusion of additives.

Hybridizing additive manufacturing (AM) structures and direct write (DW) deposition of conductive traces enables the design and physical creation of integrated, complex, and conformal electronics such as embedded electronics and complex routing on a fully AM structure. Although this hybridization has a promising outlook, there are several key AM substrate-related limitations that limit the final performance of these hybridized AM-DW electronic parts. These limitations include low-temperature processability (leading to high trace resistivity) and poor surface finish (leading to electronic shorts and disconnections). Recently discovered ultraviolet-assisted direct ink write (UV-DIW) all-aromatic polyimide (PI) provides an opportunity to address these previous shortcomings previously due to its high-temperature stability (450C) and superior surface finish (relative to other AM processes). The primary goal of this thesis is to characterize the integration of this UV-DIW PI with DW-printed conductive inks as a means for obtaining high-performance hybrid AM-DW electronics. This goal has been achieved through an investigation into the increased temperature stability of AM PI on the conductivity and adhesion of DW extrusion and aerosol jet (AJ) silver inks, determining the dielectric constant and dissipation factor of processed UV-DIW PI, and determining the achievable microwave application performance of UV-DIW PI. These performance measurements are compared to commercially-available PI film and relative to existing AM substrates, such as ULTEM 1010. The temperature stability of UV-DIW PI enabled higher-temperature post-processing for the printed silver traces, which decreased DIW trace resistivity from 14.94±0.55 times the value of bulk silver at 160 °C to 2.16±0.028 times the resistivity of bulk silver at 375 °C, and AJ silver trace resistivity from 5.27±0.013 times the resistivity of bulk silver at 200 °C to 1.95±0.15 times the resistivity of bulk silver at 350 °C. The adhesion of these traces was not negatively affected by higher processing temperatures, and the traces performed similarly on UV-DIW PI and commercial PI. Furthermore, at similar thicknesses, UV-DIW PI was found to have a similar dielectric constant and dissipation factor to commercial Dupont Kapton PI film from 1 kHz to 1 MHz, indicating its ability to perform highly as a dielectric electronics substrate. Finally, the decrease in resistivity was able to decrease the gap in microwave stripline transmission line performance when compared with ULTEM 1010 processed at 200°C, with peak 10 GHz S21 loss differences decreasing from 2.46 dB to 1.32 dB after increasing the UV-DIW processing temperature from 200 °C to 400°C.
Master of Science
Due to the extensive potential benefits and applications, researchers are looking to hybridize additive manufacturing (AM) processes with direct write (DW) techniques to directly print a 3D part with integrated electronics. Unfortunately, there are several key substrate-related limitations that hinder the overall performance of a part fabricated by hybrid AM-DW processes. Specifically, typical AM materials are not capable of providing an electronics substrate with combined sufficient surface resolution, surface finish, and high-temperature processing stability. However, the recent discovery of a novel AM-processable all-aromatic polyimide (PI) presents an opportunity for addressing these limitations as its printed form offers a high surface resolution, superior surface finish, and mechanical stability up to 400 °C. The primary goal of this thesis is to evaluate the benefits and drawbacks of this PI, processed via ultraviolet-assisted direct ink write (UV-DIW) AM, as an AM-DW electronics substrate. Specifically, the author characterized the effect of the increased temperature stability of the printed PI on the resultant conductivity and adhesion of silver inks printed via direct ink write (DIW) and aerosol jetting (AJ) DW processes. These results were also compared to the performance of the inks on commercial PI. Furthermore, the dielectric performance of printed PI was evaluated and compared to commercial PI. To demonstrate and evaluate the hybridized approach in a potential end-use application, the author also characterized the achievable microwave application performance of UV-DIW polyimide relative to the existing highest performance commercially available printed substrate material. The experiments in this thesis found an 83% and 66% decrease in resistivity from extrusion and AJ printed inks due to the ability of the printed PI to be processed at higher temperatures. Furthermore, UV-DIW PI was found to have similar dielectric properties to commercial PI film, which indicates that it can serve as a high-performance dielectric substrate. Finally, the high-temperature processing stability was able to decrease the performance gap in microwave application performance between the higher performing dielectric substrate, ULTEM 1010. These results show that UV-DIW could serve as a dielectric substrate for hybridized AM-DW electronic parts with higher performance and the ability to be deployed in harsher environments than previous AM-DW electronic parts explored in literature.

La démarche « matériaux numériques », développée au CEA Le Ripaut, consiste à optimiser numériquement une structure, à l’aide de codes de calcul permettant de réaliser des expériences numériques, afin de répondre le plus précisément possible à un cahier des charges. La mise en œuvre de ces structures optimisées, aux formes pouvant être complexes, n’est parfois pas réalisable avec les procédés de fabrication actuels. Cependant, la progression rapide de l’impression 3D semble maintenant pouvoir concrétiser cette démarche. Le but de cette thèse est d’étudier cette faisabilité de fabrication, à travers une application concrète : l’optimisation des récepteurs volumétriques des Centrales Solaires Thermodynamiques (CST).Actuellement, la conception de ces récepteurs en Carbure de Silicium (SiC) est restreinte par les techniques existantes de fabrication, et leurs morphologies se limitent donc principalement à des mousses ou des canaux parallèles. Or, ce type de structure ne permet pas d’exploiter tout le caractère 3D proposé par les récepteurs, en raison notamment d’une absorption trop hétérogène du rayonnement solaire dans le volume. Dans ce travail de thèse, afin de rechercher la répartition de l’absorption la plus homogène possible dans l’ensemble du volume, de nombreuses structures aux formes variées sont générées virtuellement. Une simulation de l’éclairement solaire reçu est réalisée sur l’ensemble de ces structures, grâce à un code de calcul développé spécialement pour cette application, permettant ainsi d’en retenir trois répondants au mieux aux critères du cahier des charges. Ces structures potentiellement optimisées ont ensuite été fabriquées en SiC par impression 3D, par un procédé de projection de liant sur lit de poudre. Elles ont été ensuite testées sur un banc d’essai expérimental du laboratoire PROMES, reproduisant les conditions d’une CST. Les résultats ont montrés que ces structures, aux formes totalement différentes de mousses ou de canaux parallèles, sont capables de produire au maximum de l’air à 860°C en sortie de récepteur, et avec des rendements énergétiques proches de 0,65. Enfin, un code de calcul thermique couplé conducto-radiatif, amélioré durant ce travail, a permis d’analyser ces résultats expérimentaux et servira pour les futurs travaux d’optimisation de la géométrie d’un récepteur
The "numerical materials" approach, developed at CEA Le Ripaut, consists to numerically optimize a structure, by using calculation codes that allow to realize numerical experiments, in order to answer, as precisely as possible, to a set of specifications. The manufacturing of these optimized structures, whose shapes can be complex, is sometimes not feasible with current manufacturing processes. However, the rapid progress of 3D printing now seems to be able to concretize this approach. The aim of this thesis is to study this manufacturing feasibility, through a concrete application: the optimization of the volumetric receivers of Concentrated Solar Power Plants (CSP). Currently, the design of these silicon carbide (SiC) receptors is restricted by the existing manufacturing techniques, and their morphologies are therefore mainly limited to foams or parallel channels. However, this type of structure does not allow to exploit all the 3D character proposed by the receivers, due in particular to a heterogeneous absorption of solar radiation in the volume. In this work, in order to find the distribution of the most homogeneous absorption possible in the whole volume, many structures with various shapes are generated virtually. A simulation of the solar irradiance received is carried out on all these structures, thanks to a calculation code developed especially for this application, thus allowing to choose three of them, respondents at best to the criteria of the specifications. These potentially optimized structures were then manufactured in SiC by 3D printing, by a binder jetting process. They were then tested on an experimental test bench of the PROMES laboratory, reproducing the conditions of a CSP. Results showed that these structures, where their shapes are totally different from foams or parallel channels, are able to produce a maximum air temperature of 860°C at the output of the receiver, and with efficiencies close to 0.65. Finally, a conducto-radiative coupled thermal computational code, improved during this work, made it possible to analyze these experimental results and will be used for the future work of optimization of the geometry of a receiver

The layer-by-layer nature of additive manufacturing (AM) allows for access to the entire build volume of a component during manufacture including the internal structure. Voids are accessible during the build process and allow for components to be embedded and sealed with subsequently printed layers. This process, in conjunction with direct write (DW) of conductive materials, enables the direct manufacture of parts featuring embedded electronics, including interconnects and sensors. The scope of previous works in which DW and AM processes are combined has been limited to single material AM processes. The PolyJet process is assessed for hybridization with DW because of its multi-material capabilities. The PolyJet process is capable of simultaneously depositing different materials, including rigid and elastomeric photopolymers, which enables the design of flexible features such as membranes and joints. In this work, extrusion-based DW is integrated with PolyJet AM technology to explore opportunities for embedding conductive materials on rigid and elastomeric polymer substrates. Experiments are conducted to broaden the understanding of how silver-loaded conductive inks behave on PolyJet material surfaces. Traces of DuPont 5021 conductive ink as small as 750?m wide and 28?m tall are deposited on VeroWhite+ and TangoBlack+ PolyJet material using a Nordson EFD high-precision fluid dispenser. Heated drying at 55°C is found to accelerate material drying with no significant effect on the conductor's geometry or conductivity. Contact angles of the conductive ink on PolyJet substrates are measured and exhibit a hydrophilic interaction, indicating good adhesion. Encapsulation is found to negatively impact conductivity of directly written conductors when compared to traces deposited on the surface. Strain sensing components are designed to demonstrate potential and future applications.
Master of Science

Da Kunststoffe im Allgemeinen einen spezifischen Oberflächenwiderstand von >10E12 Ω besitzen, müssen die Materialien zur Vermeidung von elektrostatischen Aufladungen bei Bauelementen der Elektroindustrie antistatisch ausgerüstet werden. Durch elektrostatische Aufladungen können die Bauelemente eine Beeinträchtigung ihrer Funktion erfahren und Personen gefährden. Weiterhin ermöglicht die Absenkung des spezifischen Oberflächenwiderstandes eine elektrostatische (Pulver-)Lackierung. Für die Herstellung von Kunststoffen mit kleinem spezifischen Durchgangswiderstand ist der Zusatz von leitenden Substanzen, wie z. B: Leitfähigkeitsruß, Graphit, Eisenoxid-, Kupfer- oder Aluminiumteilchen, metallisierte Glasfasern oder –kugeln, Edelstahlfasern oder Kohlenstofffasern, üblich. Die Substanzen werden dabei physikalisch in die Polymermatrix eingemischt. Je höher der Volumenanteil der Additive für die benötigte Ableitfähigkeit bezogen auf die Gesamtrezeptur ist, desto größer ist jedoch auch der Einfluss dieser Additive auf die mechanischen Eigenschaften in Relation zum unadditivierten Ausgangsmaterial. Unterschiedliche Polaritäten und Oberflächenspannungen von Additiv und Matrix bedingen zudem Probleme bei der Homogenisierung der Additive in der Matrix. Eine homogene Verteilung über das Volumen ist jedoch Voraussetzung dafür mit möglichst wenig Additiv die Perkolationsschwelle zu erreichen. Aus dieser Sicht hat sich eine reaktive Ankopplung von leitfähigen Gruppen an Matrix- oder sonstige geeignete Rezepturbestandteile in der Vergangenheit, z.B. für MDF, als erfolgreicher Weg erwiesen. Ziel war es, dieses Konzept auf duroplastische Kunststoffe zu übertragen und dessen spezifischen Oberflächenwiderstand von >10E12 Ω abzusenken. Im Rahmen dieser Arbeit sollten die Materialien SMC (Sheet molding compound) und Epoxidharzlaminate eine antistatische Ausrüstung erhalten.

La tres faible conductivite electronique de l' hydroxyde de nickel utilise a l' electrode positive de l' accumulateur nickel - cadmium rend necessaire l' ajout d' un conducteur electronique. Actuellement, les fabricants d' accumulateurs ont recours a l' addition de phases cobaltees pour ameliorer les performances de l' electrode de nickel. Ce travail est donc consacre a l' etude des differentes especes chimiques et des mecanismes impliques lors de l' utilisation d' un oxyde de cobalt du type CoO comme conducteur electronique ajoute a l' electrode positive d' une batterie nickel-cadmium. La premiere partie est relative a la caracterisation physico-chimique des phases responsables de la conduction electronique au sein de l' electrode de nickel (oxyhydroxydes de cobalt) : etude structurale par la methode de Rietveld, determination de la formulation chimique et analyse des proprietes de conduction electronique. Une etude electrochimique de ces materiaux a egalement ete effectuee a l' aide des techniques de cyclages voltamperotrique et galvanostatique. La seconde partie est relative a l' etude des mecanismes reactionnels conduisant du monoxyde de cobalt a l' oxyhydroxyde de cobalt.

Today’s state of the art additive manufacturing (AM) systems have the ability to fabricate multi-material devices with novel capabilities that were previously constrained by traditional manufacturing. AM machines fuse or deposit material in an additive fashion only where necessary, thus unlocking advantages of mass customization, no part-specific tooling, near arbitrary geometric complexity, and reduced lead times and cost. The combination of conductive ink micro-dispensing AM process with hybrid manufacturing processes including: laser machining, CNC machining, and pick & place enables the fabrication of printed electronics. Printed electronics exploit the integration of AM with hybrid processes and allow embedded and/or conformal electronics systems to be fabricated, which overcomes previously limited multi-functionality, decreases the form factor, and enhances performance. However, AM processes are still emerging technologies and lack qualification and standardization, which limits widespread application, especially in harsh environments (i.e. defense and industrial sectors). This dissertation explores three topics of electronics integration into AM that address the path toward qualification and standardization to evaluate the performance and repeatable fabrication of printed electronics for resilience when subjected to harsh environments. These topics include: (1) the effect of smoothing processes to improve the as-printed surface finish of AM components with mechanical and electrical characterization—which highlights the lack of qualification and standardization within AM printed electronics and paves the way for the remaining topics of the dissertation, (2) harsh environmental testing (i.e. mechanical shock, thermal cycling, die shear strength) and initiation of a foundation for qualification of printed electronic components to demonstrate survivability in harsh environments, and (3) the development of standardized methods to evaluate the adhesion of conductive inks while also analyzing the effect of surface treatments on the adhesive failure mode of conductive inks. The first topic of this dissertation addresses the as-printed surface roughness from individually fusing lines in AM extrusion processes that create semi-continuous components. In this work, the impact of surface smoothing on mechanical properties and electrical performance was measured. For the mechanical study, surface roughness was decreased with vapor smoothing by 70% while maintaining dimensional accuracy and increasing the hermetic seal to overcome the inherent porosity. However, there was little impact on the mechanical properties. For the electrical study, a vapor smoothing and a thermal smoothing process reduced the surface roughness of the surfaces of extruded substrates by 90% and 80% while also reducing measured dissipative losses up to 24% and 40% at 7 GHz, respectively. The second topic of this dissertation addresses the survivability of printed electronic components under harsh environmental conditions by adapting test methods and conducting preliminary evaluation of multi-material AM components for initializing qualification procedures. A few of the material sets show resilience to high G impacts up to 20,000 G’s and thermal cycling in extreme temperatures (-55 to 125ºC). It was also found that coefficient of thermal expansion matching is an important consideration for multi-material printed electronics and adhesion of the conductive ink is a prerequisite for antenna survivability in harsh environments. The final topic of this dissertation addresses the development of semi-quantitative and quantitative measurements for standardizing adhesion testing of conductive inks while also evaluating the effect of surface treatments. Without standard adhesion measurements of conductive inks, comparisons between materials or references to application requirements cannot be determined and limit the adoption of printed electronics. The semi-quantitative method evolved from manual cross-hatch scratch testing by designing, printing, and testing a semi-automated tool, which was coined scratch adhesion tester (SAT). By cross-hatch scratch testing with a semi-automated device, the SAT bypasses the operator-to-operator variance and allows more repeatable and finer analysis/comparison across labs. Alternatively, single lap shear testing permits quantitative adhesion measurements by providing a numerical value of the nominal interfacial shear strength of a coating upon testing while also showing surface treatments can improve adhesion and alter the adhesive (i.e. the delamination) failure mode of conductive inks.

Los materiales conductores mixtos de electrones e iones (oxígeno o protones) son capaces de separar oxígeno o hidrógeno de los gases de combustión o de corrientes de reformado a alta temperatura. La selectividad de este proceso es del 100%. Estos materiales, óxidos sólidos densos, pueden usarse en la producción de electricidad a partir de combustibles fósiles, así como formar parte de los procesos que forman parte del sistema de captura y almacenamiento de CO2. Las membranas de transporte de oxígeno (MTO) se pueden utilizar en las plantas energéticas con procesos de oxicombustión, así como en reactores catalíticos de membrana (RCM), mientras que las membranas de transporte de hidrógeno (MTH) se aplican en procesos de precombustión. Además, estos materiales encuentran aplicación en componentes de sistemas energéticos, como electrodos o electrolitos de pilas de combustible de óxido sólido, de ambas clases iónicas y protónicas (SOFC y PC-SOFC). Los procesos mencionados implican condiciones de operación muy severas, como altas temperaturas y grandes gradientes de presión parcial de oxígeno (pO2), probablemente combinadas con la presencia de CO2 and SO2. Los materiales más que mayor rendimiento de separación presentan y más ampliamente investigados en este campo son inestables en estas condiciones. Por tanto, existe la necesidad de encontrar nuevos materiales inorgánicos estables que proporcionen alta conductividad electrónica e iónica. La presente tesis propone una búsqueda sistemática de nuevos conductores iónicos-electrónicos mixtos (MIEC, del inglés) con diferente estructura cristalina y/o diferente composición, variando la naturaleza de los elementos y la estequiometría del cristal. La investigación ha dado lugar a materiales capaces de transportar iones oxígeno, protones o cargas electrónicas y que son estables en las condiciones de operación. La caracterización de una amplia serie de cerias (CeO2) dopadas con lantánidos proporciona una comprensión general de las propiedades estructurales y de transporte, así como la relación entre ellas. Además, se estudia el efecto de la adición de cobalto a dicho sistema. Se ha completado el análisis con la optimización de las propiedades de trasporte a partir de la microestructura. Todo esto permite hacer una clasificación inicial de los materiales basada en el comportamiento de transporte principal y permite adecuar la estructura y las condiciones de operación para obtener las propiedades deseadas para cada aplicación. Algunos de los materiales extraídos de este estudio alcanzaron las expectativas. Las familias de materiales basadas en Ce1-x Tbx O2-¿ y Ce1-x Tbx O2-¿ +2 mol% Co proporcionan flujos de oxígeno bajos pero competitivos, ya que son estables en atmósferas con CO2. Además, la inclusión de estos materiales en membranas de dos fases aumenta el flujo de oxígeno. La combinación con una espinela libre de cobalto y de metales alcalinotérreos como es el Fe2 NiO4, ha dado lugar a un material prometedor en cuanto a flujo de oxígeno y estabilidad en CO2 y en SO2, que podría ser integrado en el proceso de oxicombustión. Por otra parte, se ha añadido metales como codopantes en el sistema Ce0.9-x Mx Gd0.1O1.95. Estos materiales, en combinación con la perovskita La1- x Srx MnO3 usada comúnmente como cátodo de SOFC, han sido capaces de disminuir la resistencia de polarización del cátodo. La mejora es consecuencia de la introducción de conductividad iónica por parte de la ceria. Las perovskitas dopadas basadas en CaTiO3 forman el segundo grupo de materiales investigados. La dificultad de obtener perovskitas estables y que presenten conducción mixta iónica y electrónica se ha hecho evidente. De entre los dopantes utilizados, el hierro y la combinación hierro-magnesio han sido los mejores candidatos. Ambos materiales presentan conductividad principalmente iónica a alta temperatura, mientras que a baja predomina la conductividad electrónica tipo p. CaTi0.73Fe0.18Mg0.09O3-¿ se ha mostrado como un material competente en la fabricación de membranas de oxígeno, que proporciona flujos adecuados a la par que estabilidad en CO2. Finalmente, la perovskita La0.87Sr0.13CrO3 (LSC) ha sido dopada con el objetivo de aumentar la conductividad mixta protónica electrónica. Este estudio ha llevado al desarrollo de una nueva generación de ánodos para PC-SOFC basadas en electrolitos de LWO. Las perovskitas dopadas con Ce en el sitio del La (LSCCe) y con Ni en el sitio del Cr (LSCN) son estables en condiciones de operación reductoras, así como en contacto con el electrolito. El uso de ambos materiales como ánodo disminuye la resistencia de polarización con respecto al LSC. El LSCCe está limitado por los procesos que ocurren a baja frecuencia (BF), relacionados con los procesos superficiales, y que son atenuados en el caso del LSCN debido a la formación de nanopartículas de Ni metálico en la superficie. La infiltración posterior con nanopartículas de Ni permite disminuir la resistencia a BF lo que sugiere que la reacción superficial de oxidación del H2 está siendo catalizada. La infiltración más concentrada en Ni (5Ni) elimina completamente la resistencia a BF en ambos ánodos, de forma que los procesos que ocurren a altas frecuencias son ahora limitantes. El ánodo constituido por LSCNi20+5Ni dio una resistencia de polarización de 0.26 ¿·cm 2 at 750 ºC en H2 húmedo.
Mixed ionic (oxygen ions or protons) and electronic conducting materials (MIEC) separate oxygen or hydrogen from flue gas or reforming streams at high temperature in a process 100% selective to the ion. These solid oxide materials may be used in the production of electricity from fossil fuels (coal or natural gas), taking part of the CO2 separation and storage system. Dense oxygen transport membranes (OTM) can be used in oxyfuel combustion plants or in catalytic membrane reactors (CMR), while hydrogen transport membranes (HTM) would be applied in precombustion plants. Furthermore, these materials may also be used in components for energy systems, as advanced electrodes or electrolytes for solid oxide fuel cells (SOFC) and proton conducting solid oxide fuel cells (PCSOFC) working at high and moderate temperature. The harsh working conditions stablished by the targeted processes include high temperatures and low O2 partial pressures (pO2), probably combined with CO2 and SO2 containing gases. The instability disadvantages presented by the most widely studied materials for these purposes make them impractical for application to gas separation. Thus, the need to discover new stable inorganic materials providing high electronic and ionic conductivity is still present. This thesis presents a systematic search for new mixed ionic-electronic conductors. It includes different crystalline structures and/or composition of the crystal lattice, varying the nature of the elements and the stoichiometry of the crystal. The research has yielded new materials capable to transport oxygen ions or protons and electronic carriers that are stable in the working condition to which they are submitted.
Balaguer Ramírez, M. (2013). New solid state oxygen and hydrogen conducting materials. Towards their applications as high temperature electrochemical devices and gas separation membranes [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/31654
TESIS
Premiado

L’étude de l'électrocatalyse des réactions de réduction de l'oxygène (RRO) et de dégagement de l'oxygène (RDO) est étroitement reliée au développement de matériaux cathodiques et anodiques pour les piles à combustible et les électrolyseurs. L’objectif de cette thèse est de développer et d’étudier des matériaux d’électrodes à base d’oxydes de Mn et de Co, actifs et stables, à la fois pour la RRO et la RDO. Les relations entre les caractéristiques électrochimiques des compositions pérovskite / carbone et les propriétés de leurs composants sont établies et étayées expérimentalement dans la thèse. Il a été constaté que la résistance des matériaux carbonés à la corrosion dans les conditions de la RDO est influencée non seulement par leur ordre cristallin, mais également par leur activité intrinsèque pour la RDO. Il a été démontré que les activités des pérovskites à base de Mn et de Co dépendent linéairement du nombre de cations de Mn et de Co rechargeables, respectivement pour la RRO et la RDO. Il a été découvert qu'une intercalation réversible de l'oxygène dans la structure cristalline des pérovskites à base de Co se produit dans les conditions de la RDO, ainsi qu'à des potentiels plus faibles
A study of electrocatalysis of oxygen reduction (ORR) and oxygen evolution (OER) reactions is closely related with a development of cathodic and anodic materials for fuel cells and elec-trolyzers. An objective of this thesis is to develop and investigate Mn, Co-oxide-based elec-trode materials active and stable in both the ORR and OER. Relationships between electro-chemical characteristics of perovskite/carbon compositions and properties of their compo-nents are stated and experimentally substantiated in the thesis. It is found a corrosion re-sistance of carbon materials under OER conditions is influenced not only by their crystalline order, but also by their intrinsic OER activity. It is shown the ORR and OER activity of Mn, Co-based perovskites linearly depends on the number of rechargeable Mn and Co cations, respectively. It is revealed a reversible oxygen intercalation through a crystal structure of Co-based perovskites occurs under OER conditions as well as at lower potentials

Nous presentons la premiere mise en evidence d'une phase ferromagnetique dans des heterostructures a puits quantique semimagnetique cdmnte/cdmgznte dopees p par modulation (azote) dans les barrieres. Dans de tels echantillons, le transfert de trous des barrieres dans le puits cree un gaz de trous quasi-bidimensionnel dans la couche de cdmnte. Pour optimiser les conditions de dopage, une etude preliminaire a ete menee sur une serie d'echantillons a puits quantiques non magnetiques cdte/cdmgznte montrant que, dans des puits de 80 a, le gaz de trous devient metallique pour des densites superieures a 1. 5 x 10#1#1 cm#-#2. En outre, ces echantillons nous ont permis d'observer les deux types d'excitons charges x#+ et x#-. Dans les echantillons a puits semimagnetique cdmnte, l'interaction d'echange entre les ions magnetiques mn#+#+ et le gaz de trous en phase metallique ( 2 x 10#1#1 cm#-#2) cree un couplage ferromagnetique du type rkky entre les spins localises des ions mn#+#+. Dans des puits d'une largeur de 80 a et pour des concentrations de mn d'environ 3%, l'interaction ferromagnetique induite par le systeme de trous bidimensionnel devient superieure au couplage antiferromagnetique de superechange entre les ions magnetiques mn#+#+. Ceci se traduit par une transition de phase ferromagnetique a la temperature critique t#c d'environ 2 k. La phase paramagnetique au dessus de t#c est caracterisee par une augmentation spectaculaire de la susceptibilite magnetique.

Abstract The qualitative and quantitative characteristics of each component layer constituting the structure of organic bulk heterojunction solar cells (OSC-BHJ) contribute significantly towards its overall performance. One of the prevalent issues resulting in reduced device efficiency is due to the conformational inhomogeneities in the active and buffer layers. The mechanical stress, extended thermal exposure and presence of mutually reactive component layers etc., affects negatively on the device stability. Effective methods to address these issues will be extensively benefited by the industry since the current commercialisation of the technology is hindered owing to the lower efficiency and stability of these devices. This dissertation focuses on methods to coherently enhance the performance and longevity of the OSC-BHJ devices. The efficiency enhancements of the devices in this work were achieved through two main routes. The first route was through morphological improvement of the active layer. The second route was through boosting the electrical characteristics of hole transporting conducting polymer layer (HTL) by controlled annealing conditions. The introduction of a suitable additive in the active layer was found to reduce unfavourable phase segregation thus resulting in enhanced morphology. Further, the annealing conditions in different atmospheres (air, nitrogen and vacuum) were found to have a clear influence on the optimum functioning of the HTL in the device. Regarding the stability improvement study done in this work, a method of employing suitable interlayer was developed to effectively abate the internal degradation occurring in the device due to etching reaction on the indium tin oxide (ITO) anode by the HTL. Moreover, experimental investigations were carried out for drawing fundamental understanding of stability degenerating issues such as the influence of mechanical defects on transparent conducting metal oxide (ITO) anode on the performance of the device and heat induced degradations in the low band gap polymer-fullerene active layer. The highlight of this research is that the discovered methods are inexpensive, efficient, and easy to adopt. The results of the study could help the technology to overcome some of its limitations and accelerate its progress towards commercialisation
Tiivistelmä Orgaanisten heteroliitosaurinkokennojen kerrosrakenteen ominaisuudet ja laatu vaikuttavat merkittävästi aurinkokennojen toiminnallisuuteen. Erityisesti rakenteelliset epähomogeenisuudet aktiivi- ja puskurikerroksissa heikentävät kennon hyötysuhdetta. Kennojen stabiilisuutta tarkasteltaessa myös mekaanisella rasituksella, pitkittyneellä lämpöaltistuksella ja materiaalien reagoinneilla keskenään kerrosten välillä, on selkeä negatiivinen vaikutus kennojen stabiilisuuteen. Orgaanisen aurinkokennoteknologian kaupallistamisen rajoitteina ovat kennojen heikko hyötysuhde ja stabiilisuus, joten menetelmät jotka tarjoavat ratkaisuja edellä mainittuihin ongelmiin, ovat erittäin tärkeitä teknologiaa kaupallistavalle teollisuudelle. Tämä väitöskirja keskittyy johdonmukaisesti selvittämään tapoja, joilla voidaan parantaa heteroliitosaurinkokennojen hyötysuhdetta ja elinikää. Hyötysuhteen tehostamiseksi valittiin kaksi eri lähestymistapaa, joista ensimmäisessä keskityttiin aktiivikerroksen morfologian parantamiseen ja toisessa aukkoja kuljettavan kerroksen sähköisten ominaisuuksien parantamiseen lämpökäsittelyprosessin avulla. Sopivan lisäaineen avulla aktiivikerroksen ei-toivottua kiteytymistä voidaan pienentää ja parantaa näin kerroksen morfologiaa. Lisäksi työssä todettiin, että lämpökäsittelyn aikaisella ympäristöolosuhteella (ilma, typpi, tyhjiö) on merkittävä vaikutus puskurikerroksen optimaaliseen toimintaan aurinkokennossa. Stabiilisuuden parantamiseksi kehitettiin välikerroksen hyödyntämiseen perustuva menetelmä, jolla voidaan tehokkaasti vähentää kennojen sisäisessä rakenteessa tapahtuvaa toiminnallisuuden heikkenemistä, joka aiheutuu aukkoja kuljettavan kerroksen syövyttävästä vaikutuksesta indiumtinaoksidi (ITO) pohjaiseen anodiin. Tämän lisäksi työssä tutkittiin kokeellisesti stabiilisuuteen heikentävästi vaikuttavia tekijöitä, kuten mekaanisen rasituksen aiheuttamia vaurioita metallioksidi (ITO) anodissa ja lämpöaltistuksesta aiheutuvia vikoja polymeeri-fullereeni rakenteeseen perustuvassa aktiivikerroksessa. Tutkimuksen keskeisin tulos on, että esitellyt keinot aurinkokennojen hyötysuhteen ja stabiilisuuden parantamiseen ovat edullisia, tehokkaita ja helppoja hyödyntää. Tulokset voivat merkittävästi edistää orgaanisten aurinkokennojen teknistä kehitystä ja kiihdyttää niiden tuloa kaupallisiksi tuotteiksi

Onze bis (selenopyrannylidenes)-4 :4' ont ete synthetises par duplication de selenopyrannethiones-4 ou de perchlorates de selenopyrylium. Des analyses microscopiques, thermodifferentielles, structurales ont indique que certains perchlorates de selenopyrylium sont des smectiques a alors que les bis (selenopyrannylidenes)-4 : 4' correspondants ne semblent presenter que des phases de type cristal plastique. L'etude cristallographique et des potentiels d'ionisation et d'oxydo-reduction a montre leur interet comme donneurs d'electrons pi dans des conducteurs organiques. Des complexes a transfert de charge avec le tcnq et la ddq et des sels d'ions radicaux avec l'iode et divers contre-ions ont ete obtenus et etudies du point de vue de leurs proprietes structurales, electriques, optiques et magnetiques. Certains d'entre eux possedent un caractere metallique

碩士
國立中央大學
光電科學與工程學系
104
The optoelectronic device with the trending minimization of application, often affect the electrical properties on thermal drift or breakdown device by thermal stress, it is required the compound silicone with thermal conductive components to transfer heat and to assist heat from the device, that consider simultaneously the electrically insulating or install with flexibility on mechanism, thereby simplifying the production process also improves the reliability of the product. Different proportions of the compound silicone has a different thermal resistance RM and thermal conductivity kM, this research paper, in accordance with 1 ~ 4μm particle size and 120 ~ 150[W/m℃] thermal conductivity value range, to selecting the Graphite, Silicon carbide (SiC) and Aluminum nitride (AlN) that three additive materials is common in market, which the black graphite and silicon carbide is a conductor, aluminum nitride is an insulator. Compound silicone were measured by using standard ASTM D5470, it must take more than two hours to steady state heat, then get the correct measured value of RM and kM , Derived formula of RM and kM with heat transfer theory and the principles of derived heat volume for calculate the theoretical value to comparing measured value. Then can be available the maximum ΔRM is 0.20 [℃/W], the smallest tolerance is 0.01 [℃/W] ,while the maximum tolerance ΔkM is 0.11[W/(m∙℃)], the minimum tolerance is 0.01[W/(m∙℃)], that can be proved which the theoretical formula have useful reference in academic, and this can provide a quick calculation to predict heat transfer characteristics of the compound silicone in the relevant industry. The conclusion that physical properties of the thermal conductive compound silicone: kM is no significant effect changes within mixing less than 30wt% conductive material as Graphite or SiC, then proportional increase kM until adding conductive material more than 40wt%, this is superior to AlN until more than each 68wt% mixing ratio. But the mechanical strength of the compound silicone is fragile when more than 85wt% mixing ratio. The RM of more than 75wt% AlN compound silicone less than the same ratio of SiC is good thermal conductivity. The 80wt% AlN compound silicone is better transferable heat and kM = 0.85.

碩士
國立臺灣科技大學
營建工程系
94
This research used the same water-binder ratio (W/B = 0.6) to study the effects of fly ash or slag on the properties of concrete under steam curing. This study also used a one-dimensional heating test module of 7 × 7 × 55 cm to study the effects of fly ash and slag on the thermal conduction of concrete, and to compare the difference of properties of harden concrete at the locations away from the heating surface. Experimental results show that: (1) The hydration and Pozzolanic reaction speeded up by steam curing, such that the 3-day compressive strength of steam-cured concrete was higher than that of the water cured, and this condition becomes more obvious with more Pozzolanic replacement, especially for fly ash; (2) The surface electrical resistivity of the steam-cured concrete with fly ash was much higher than the water-cured , and had a substantial increase with even higher fly ash replacement; (3) The thermal conducting speed of fresh concrete was obviously higher, which showed that the degree of saturation had a positive correlation with the thermal conductivity rate; (4) After 28 day, the thermal conductivity rate of concrete with the replacement of 30% slag was much lower than the others; the replacement of 30% fly ash (F30) and 15% slag (S15) were the next high, and the normal-weight concrete and mortar were the highest; (5) The difference in the properties of harden concrete at different layers in the one-dimensional heating test were not apparent, due to the fact that, during the earlier stage of the test, the concrete specimens were also subjected to the thermal conduction from the surrounding lateral surfaces.

碩士
國立中山大學
光電工程學系研究所
102
In this study, we synthesized a series of N-alkylimidazole derivatives that we used to decrease the silver (Ag) metal percentage in silver pastes while maintaining the volume resistivity of a silver conductive paste with cellulose-base containing 58-70% Ag metal. We formulated the organic vehicle by blending ethyl cellulose, sorbitan trioleate, tributyl citrate, and terpilenol (as solvent) in abundances of 22, 25, 27, and 30 wt. %, respectively, relative to the silver paste. The organic vehicle and the additive material, an N-alkylimidazole (CnIm), were mixed to form a homogeneous electrically conductive paste. Piece shaped silver having a median particle diameter of 10 μm were added at 50, 58, 64, or 70 wt. % relative to the silver paste; the optimal additive material, C6Im, was added at 5, 9, 17, or 28 wt. % relative to the paste. We developed a homogeneous thick film of the electrically conductive silver paste; the sintered homogeneous paste had a volume electrical resistivity of 10–5 Ω‧cm at a Ag content of just 58 wt. %. Besides, comparison to a commercial Ag paste, C1Im and C6Im can enhance the conductivity of 67.6%, 52.5%, respective. Piece shaped silver were added at 67wt.% relative to Ag paste; C1Im and C6Im both were added at 5wt.% relative to Ag paste under sintering temperature at 170℃ for 1 hour. Sintered pastes not only maintained volume electrical resistivity of 10–5 Ω-cm but reduced the content of silver approximately within 15-17%. When C6Im was the additive, scanning electron microscopy revealed that a small quantity of fine Ag particles had a large surface area, bringing more of the particles into contact so that they fused together to form an electrically conductive network.

碩士
國立臺灣科技大學
營建工程系
102
The study mainly investigated the effects of electrical and thermal properties of concrete with the addition of steel fiber and graphite designed by volume method. The results indicate that the addition of steel fiber will increase the strength of concrete whereas the addition of graphite tends to decrease the strength. For electrical properties, the mixture proportion with 0.75% steel fiber and 7% graphite by volume have the better conductivity. The electrode spacing under air curing condition has large conductivity differences, and such condition the conductivity contribution from conductive material is obvious. The specimen under water curing shows the lowest conductivity as compare to other curing method. For the thermal properties, the epoxy coated specimen has the most stable heating efficiency, and after conducting for 3 hours, the temperature increase about 7 to 10 ˚C under 10˚C environment. The corresponding electric power per square meter is between 125 to 187 W. The material cost of the mixture proportion without using conductive material has the lowest cost and highest power cost-performance ratio. It is suggested to use epoxy coating to maintain the humidity inside conductive concrete, and that not only enhance the heating power but also reduce the conductive material used as consequence reduce the material cost.

碩士
國立中山大學
化學系研究所
107
In recent years, electrically conductive adhesives (ECA) comprised of epoxy resin and metal fillers are crucial for efficient thermal management. However, inhomogeneous accumulation of silver flakes tends to form voids which may decrease the efficiency of heat transfer and conductivity. Through metallo-organic-decomposition (MOD) technique, we added silver 2-ethylhexanoate into ECA production. The measurements show that both the electrical and thermal conductivity are increased. SEM images show that silver nanoparticles are well dispersed in epoxy, and the cross-section SEM image indicate the newly formed continuous after the addition of silver 2-ethylhexanoate. EDS and XPS prove that these nanoparticles are pure silver. The density measurements of AgEH-ECA samples clearly exhibit the higher values than the AgEH-free ones, corresponding to the cross-section SEM results which show dense stacking of silver. We also varied the amounts of silver 2-ethylhexanoate in ECA and the curing temperatures to achieve optimal thermal and electrical performance. The die shear strength is shown improved when adding AgEH to ECA. Addition of silver 2-ethylhexanoate was evident to result in silver nanoparticle formation after annealing which fills out the voids without significant viscosity change and Ag nanoparticle aggregation.

碩士
國立清華大學
材料科學工程學系
104
The lithium-sulfur batteries show significant potential for next-generation energy storage systems, due to its high specific capacity of 1675 mAh/g and theoretical energy density of 2600 Wh/kg are 3-5 times higher than conventional lithium ion battery. Furthermore, sulfur show advantages of low cost, environmental benign, and naturally abundant. The present work attempted to use Ti4O7 conductive metal oxide as an additive in the cathode to increase cycling performance owning to its high electric conductivity and chemical binding of soluble polysulfides. At the first part, the Ti4O7 was introduced to pure sulfur system through slurry mixing process. The results showed that the addition of 37.5 % to 50 % Ti4O7 could improve cycle life and capacity retention. From EIS measurement, we found that the charge transfer resistance was significantly reduced by addition of appropriate amount of Ti4O7. At the second part, the Ti4O7 was introduced to Graphene-S composite system through slurry mixing process. The results showed that the addition of 25 % to 50 % Ti4O7 could reduce charge transfer resistance and improve the capacity performance and cycle life. In addition, using Graphene-S composite as active material could lead to better sulfur utilization than pure sulfur system. At the third part, the Ti4O7 and conductive carbon black Super P were coated on the commercial polypropylene separator by doctor blade method. The functional coating layer has been investigated to improve the electrochemical performance of lithium-sulfur battery, and served as an upper current collector to facilitate electron transport and a conductive network for trapping and depositing dissolved polysulfides.

碩士
靜宜大學
應用化學研究所
98
Because of the worldwide concern about energy source and environment, the development of energy storage products and technologies has been paid highly attention to. Lithium ion battery is one of the most potential energy storage products now. Mesophase graphite powder(MGP) is spherical material with lamellar microstructure and with good performance as an anode material of lithium ion battery. However, the thermal expansion of the electrode will easily spoil the connection between each Mesophase graphite sphere. By adding fibrous conductive additive, Vapor Growth Carbon Fiber (VGCF), the linkage of condcutive channel of graphite spheres will be effectively improved. Nevertheless, the dispersing method of VGCF is the key process of this technology. In this research, the nonionic surfactant, Hypermer KD-1(KD-1) and Polyvinylpyrrolidone K30 (PVP K30) were chosen to improve the dispersity of Mesophase graphite powder and VGCF. The rheometer was applied to analyze rheological properties of anode slurries with different recipes. And the micro-image of electrodes by SEM and uniformity of resistance on electrodes by resistance analyzer were used to understand the relationship between concentration and types of surfactant and dispersity of VGCF. The electrode expansion ratio was tested to prove the influence of VGCF on electrode structure. Then the discharge capacity and the first cycle irreversible loss of the coin-type cells made of the electrodes respectively were tested. The discharge rate test and cycle life test of LiCoO2+ LiNi0.33Co0.33Mn0.33O2/MGP+VGCF cell were tested to check the effectiveness of surfactants and dispersity of VGCF on the performance of cell.

碩士
中原大學
機械工程研究所
106
This study mainly analyzes the plastics material, ABS, one of the insulating material. There is a major concern that static electricity might remain on the surface of ABS product after manufacturing. The static electricity may cause personnel to suffer electrostatic discharge problems or may have accidents in working environment. In this study, polymer materials with anti-static properties were added to ABS to become a composites material with static dissipation properties. From the experiments performed, material properties of ABS including surface electrical properties, static dissipation, penetration, and mechanical properties such as hardness and tensile strength could be discovered. In the study, different proportion between ABS and the conductive polymer with anti-static properties were analyzed. The difference in material temperature, mold temperature and additive ratios could generate 11 combinations for data analysis. By adding different proportions of material, the pull-out strength shows an upward trend when the material temperature and the mold temperature were increasing. Through the increase in the proportion of conductive polymer, the data obtained after surface electrical and electrostatic dissipation tests presented an upward trend as well. When the proportion of conductive polymer increases, the hardness, tensile strength, and penetration rate tend to decrease. Based on the above results, the proportion of conductive polymer can change the characteristics of ABS raw material. , and the difference in proportions has a great influence also.

碩士
中原大學
化學工程研究所
106
In this study, a green, facile, low-cost and scalable industrial method using jet cavitation (JC) is utilized to prepare graphene conductive additive and applied to a lithium-ion battery. The study is divided into three parts. In the first part, delamination of artificial graphite and natural graphite by jet cavitation to prepare few layer graphene (MoCPCB and Mo8) is studied. According to AFM analysis, more than 80% the layer of few layer graphene is less than 5 nm (10 layers). In the Raman analysis, the D/G ratio of MoCPCB is 0.24, and the D/G ratio of Mo8 is 0.19, which is lower than the graphene produced by Hummers method. Next, the as-prepared graphene is applied as conductive additive for lithium ion battery. Graphene is also mixed with commercial conductive carbon black for comparison. The battery with MoCPCB 7% SP 3% has an average capacity of 144.6 mAh/g at 0.1 C and 131.0 mAh/g at 1 C. The battery with Mo8 3% SP 7 % has an average capacity 154.0 mAh/g at 0.1 C and 142.1 mAh/g at 1 C. These two conductive additive ratios deliver the best C-rate performance compared to commercial KS6. In the second part, the effects of different methods to add conductive additives to improve the C-rate performance is investigated. The battery with liquid-phase conductive additives has an average capacity 149.8 mAh/g at 0.1 C, 142.9 mAh/g at 1 C and 91.8 mAh/g at 10 C with a retention of 61.2%. This method is found to be more effective than using solid-phase method to prepare the conductive additive. Lastly, the effect of different amount conductive additives on the C-rate performance through liquid-phase method is examined. It is found that the optimum electrochemical performance of the battery is achieved by adding 4% conductive additive. An average capacity of 137.3 mAh/g(electrode) and 125.3 mAh/g(electrode) are obtained at 0.1C and 1C, respectively. At 10 C, the average capacity is 56.2 mAh/g(electrode) with a capacity retention of 41.0 %. A continuous, facile and scalable approach to prepare graphene for conductive additive applications is successfully obtained through jet-cavitation technique. It is effectively applied as conductive additives for the cathode in lithium-ion batteries. The obtain results showed potential commercial applications in the future.

The covalent bond formed between a N-heterocyclic carbene and an aryl-isothiocyanate was discovered to be thermally-reversible. This bond was incorporated into the backbone of an aromatic polymer which, when subjected to heat and excess monomer, would depolymerize to smaller oligomers. In addition these small molecules contain active chain ends and could be repolymerized to reform the original polymer. The high molecular weight material was made into freestanding sheets with desirable mechanical properties and could be made conductive by treatment with iodine. A new poly(triazene) was formed from the reaction of a facially opposed, annulated, bis-N-heterocyclic carbene (NHC) and an organic bis-azide. The NHC as well as the azide were varied and combined to produce a series of polymers which were characterized by GPC, TGA, and NMR. These thermally robust polymers were also coated onto glass slides and rendered electrically conductive by exposure to iodine vapor. A new reagent for Reversible Addition Fragmentation Chain Transfer Polymerization (RAFT) is described. This imidazolium based reagent shows unusually fast kinetics which allows it to control polymerizations at significantly reduced loadings compared to the more traditional neutral dithiocarbamates or dithioesters. The fast kinetics is explained by the rapid rotation of the dithioester about the plane of the cationic N-heterocycle. Sulfonated poly(ether ether ketone) (sPEEK) membranes were blended with imidazoles with varying pKas. The proton conductivity of the membranes was evaluated as a function of pKa and temperature. Interestingly, the conductivity of the dry membranes showed a non-monotonous profile over a temperature range of 25 – 150 C. We use a theoretical model to better understand the mechanistic origins of the observed temperature–conductivity profiles. This model is based on the reaction equilibria between sPEEK’s sulfonic acid groups and the basic sites of the added heterocycles. Using the copper-catalyzed 1,3-dipolar “click” cycloaddition reaction, poly(sulfone)s containing pendant azide moieties were functionalized with various amounts of sodium 3-(prop-2-ynyloxy)propane-1-sulfonate and crosslinked with 1,7-octadiyne. The degree of sulfonation as well as the degree of cross-linking was systematically varied by changing the ratios of the aforementioned reagents. The polymers were cast into membranes, acidified, and then tested for proton conductivity, methanol permeability, and membrane-electrode assembly (MEA) performance.
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碩士
國立清華大學
材料科學工程學系
106
Due to the advantages of low cost, non-toxic and high theoretical specific capacity (1675 mAh/g), lithium-sulfur (Li-S) battery is regarded as the most promising candidate for the next generation rechargeable battery. Three main drawbacks resulting Li-S battery not being able to be widely used in market include the insulating nature of sulfur, 80% volume expansion and polysulfide shuttle mechanism. The dissolution of polysulfide into the electrolyte is the major reason for the capacity decay. Herein, we used Al3+ doped cubic Li7La3Zr2O12 (LLZO), which belongs to garnet-type lithium-ion conductor, as cathode additive and mixed with super P as the interlayer. The sulfur sources investigated are nano-sulfur and Ketjen black-S (KB-S) carbon-sulfur composite. The results of batteries with addition of LLZO as cathode additive and the nano-sulfur as active material, showed higher discharge specific capacities compared to those without LLZO. Because of the insulating nature of LLZO, the charge transfer resistance of batteries have increased with increasing amount of added LLZO. The other part is to apply LLZO-super P composite slurry on the Celgard PP separator as an interlayer between cathode and separator. The result illustrated that LLZO-super P interlayer could prolong the cycle life and enhance the electrochemical performance and the best promotion came from with the ratio LLZO/super P = 4 when it was applied with nano-sulfur active material. For KB-S active material, the carbon composition of KB-S had the best cooperation with 100% super P interlayer.

碩士
國立清華大學
材料科學工程學系
102
Rechargeable lithium sulfur cell has become the next-generation energy storage system owing to its theoretical capacity of 1673 mAh/g is 5 times higher than current state of layer-like lithium ion cell based on intercalation mechanism. The discharge/charge of electrode is formed with cleavage/formation, therefore its quantity of reactive lithium ions are not constrained by the structural stability.The present work attempts to study the characteristics of liquid-based lithium sulfur cell with lithium co-salt of LiNO3. At the first part, the study examines how the cut-off voltage region and addition of electrolyte volume (E/S ratio) affect the earlier stage of discharge capacity and middle/later stage of cycle retention. At the second part, water soluble Li3PO4 of ionic conductor is introduced to the lithium sulfur system. The study compares the electrochemical performance by using cycle voltammetry method, AC impedance method, X-ray diffraction and SEM analysis. The results suggest that the addition of 16.7 to 25 % Li3PO4 of conductive agent shows the uniform distribution on the electrode after charge/discharge, therefore they have better rate capability and cycle performance. Such a simple method for the construction of electrode scaffolds shows potential for high C-rate performance lithium sulfur batteries.

碩士
義守大學
材料科學與工程學系
92
Conductive adhesives have been commercially available for decades and are widely used in the electronics industry such as COG（Chip on Glass, COG）, COB（Chip on Board, COB）, LCD（Liquid Crystal Display, LCD）modules assembly applications. To get a high performance conductive adhesive electrically, the geometry, size, and percentage of the filled particles are crucial factors. In addition, the applied dilute solvent, eliminating bubbles resulting from preparation processes, and proper curing temperature are also important factors to be considered. In this investigation, various amounts of flake, dendrite and sphere silver powders and copper powders are used as conductive fillers and mixed in an Epoxy 828 resin. DPM, BCA, XYLENE and dispersant are added as dilute solvent to keep filler particles distributed uniformly in the resin. Curing temperatures are set at 175oC, 190oC and 210oC and an optimum condition for processing conductive adhesives is determined. The mechanism of conductivity achievement in conductive adhesives is analyzed by comparing processing conditions, resistivity and microstructures (both OM and SEM observations). Furthermore, the influence of adding nano-sized silver particles and copper particles on the resistivity of the conductive adhesives is also investigated.