3D electrode design

D ELECTRODE DESIGN BY NEW ELECTRODE PROCESSING TECHNIQUES graphite foil electrodeposition... 

In the earlier studies, cells were designed specifically for each type of 3D electrode, but more recently 3D electrodes have been incorporated into conventional parallel plate cells and/or stacks. Often, the electrodes are fabricated from cloths or meshes rather than from thicker materials and, as a result, the current scaling is more modest but still significant. Cloth and felt electrodes within parallel plate cells are common in vanadium flow batteries. 

Developments in both design and materials have greatly improved the performance of parallel plate cells, including the incorporation of features such as 3D electrodes from academic studies. Unfortunately, Electrochemical Engineering has not matured as an academic subject in the way that Martin Fleischmann would have wished, and it remains poorly... 

The apphcation of porous, conductive scaffolds as components of anode architectures can enhance power production by three processes (1) transporting fuel from the bulk solution to the surface-confined biocatalysts, (2) increasing the amount of 3D surface area suitable for enzyme immobilization or biofilm formation, and (3) enhancing conductivity and, in turn, ET between the biocatalyst and the electrode. When considering electrode design, the support should be biocompatible and highly conductive at the same time. Additionally, the scaffold should have enough porosity to enhance mass transport of fuel. 

The fuel cell is basically a two-scale system. The small and large scales are determined, respectively, by membrane-electrode assembly (MEA) thickness and by the length of the feed channel. The Q3D model is designed to investigate the interplay of small- and large-scale processes in PEFC/DMFC, so that the fully 3D model of the cell is split into a model of a cell cross section (internal model) and a model of the flow in the channel (channel model). The two models are coupled via the local current density along the channel and the overall Q3D solution is obtained by iterations. 

The evaluation of elements valences (charge state of an atom in compound with the ionic type of chemical bond) is especially needed for studying and designing such materials as mixed valence semiconductors based on 3d-transition metal oxides. The preliminary set electron or hole current carrier density in such materials can be created by applying the valence regulation method. Such electroconducting oxide materials are widely used as electrodes of fuel cells and other current sources, gas sensors, electric heating elements, thermistors etc. 

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