Cathode microstructural parameters

In actual manufacturing of cathode, the processing parameters have significant impact on the microstructural, hence, impact on the SOFC properties. For example, the following processing and microstructural parameters are important in LSMAfSZ cathode [16] ... 

Haanappel, V.A.C., Mertens, )., Rutenbeck, D., Tropartz, C., Herhof W., Sebold, D., and Tietz, F. (2005) Optimisation of processing and microstructural parameters of LSM cathodes to improve the electrochemical performance of anode-supported SOFCs. J. Power Sources, 141, 216—226. 

In addition to the use of composite anodes and cathodes, another commonly used approach to increase the total reaction surface area in SOFC electrodes is to manipulate the particle size distribution of the feedstock materials used to produce the electrodes to create a finer structure in the resulting electrode after consolidation. Various powder production and processing methods have been examined to manipulate the feedstock particle size distribution for the fabrication of SOFCs and their effects on fuel cell performance have also been studied. The effects of other process parameters, such as sintering temperature, on the final microstructural size features in the electrodes have also been examined extensively. 

There is clearly a microstructural dependence, and studies on HAZs show corrosion to be appreciably more severe when the material composition and welding parameters are such that hardened structures are formed. It has been known for many years that hardened steel may corrode more rapidly in acid conditions than fully tempered material, apparently because local microcathodes on the hardened surface stimulate the cathodic hydrogen evolution reaction. (Bond)5... 

Mesoscale modeling of SOFCs focuses on modeling the transport and reactions of gas species in the porous microstructures of the electrodes [3, 34, 56-59]. In these models, the porous microstructure is explicitly resolved, which negates the need for the effective parameters of macroscale models. The transport and reactions of species in mesoscale models are described by the species [Eq. (26.1)], momentum [Eq. (26.5)], and energy [Eq. (26.7)] conservation equations, which are solved at the pore scale. At the pore scale, the conservation equations are solved in two separate domains the solid domain of the tri-layer and the gas domain of the pore space within the tri-layer. Mesoscale models aim to understand the effects of microstructure and local conditions near the electrode-electrolyte interface on the SOEC physics and performance. These models have been used to investigate a number of design and degradation issues in the electrodes such as the effects of microstructure on the transport of species in the anode [19, 56] and the reactions of chromium contaminants in the cathode [34]. 

Electrocatalysts advocated for methanol oxidation at the anode and oxygen reduction at the cathode in DMFCs are required to possess well-controlled structure, dispersion, and compositional homogeneity [46 9]. The electrocatalytic activities of both anode and cathode catalysts are generally dependent on numerous factors such as particle size and particle size distribution [50-54], morphology of the catalyst, catalyst composition and in particular its surface composition [55,56], oxidation state of Pt and second metal, and microstructure of the electrocatalysts [49,57,58]. With the frequently attempted surface manipulation strategies for nanosized electrocatalysts to increase their catalytic efficiencies toward MOR and ORR, rigorous characterization techniques which can provide information about nanoscale properties are critically required. For example, parameters such as particle size and variation in surface composition have strong influence on catalytic efficiency. Further, if the nanoparticles are comprised of two or more metals, both the composition and the actual distribution will... 

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