Electrolyte ultra-thin layer

Microelectrodes, also called ultra-microelectrodes, have some very special diffusion properties. The electrode can be prepared by melting an ultra-thin metal wire into a glass rod. The small radius of the wire with only a few micrometers leads to a situation in which the radial resistance of the electrolyte in front of the electrode snbstitntes the diffusion limitation by the diffusion layer. A microelectrode and the current distribution in front of the microelectrode are shown in Figure 5.14. 

Its specific resistivity should not exceed 20 ohm cm. This criterion is particularly important for large, rechargeable batteries (e.g. traction batteries) where high power levels are involved and electrical efficiency is a key parameter, but it may be less important for small, low power batteries, particularly those designs which utilise ultra-thin electrolyte layers. 

The investigation of the outdoor corrosion of metals like steel, weather resistant steel, galvanized steel, copper, etc., as during the daily wet/dry cycling ultra-thin electrolyte layers are formed, which are of ultimate importance for the average corrosion rate and which cannot be analyzed by conventional electrochemical techniques (Sec. 7.4.5). 

Wilson, M.S. and Gottesfeld, S., High performance catalyzed membranes of ultra-low Pt loadings for polymer electrolyte fuel cells, J. Electrochem. Soc., 139, L28, 1992. Wilson, M.S. and Gottesfeld, S., Thin-fihn catalyst layers for polymer electrolyte fuel cell electrodes, J. Appl. Electrochem., 22, 1, 1992. 

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