IMPEDANCE STUDIES OF POROUS-ELECTRODES

Various approaches to the application of impedance methods to the study of porous electrodes are reviewed with reference to two examples. These are: (i) double-layer charging in porous structures; (ii) fuel cell gas-diffusion electrodes. Simple pore models are described first, and their extension to cases with charge-transfer and mass transport is then discussed. The thin film and distributed agglomerate models for gas electrodes are also described, and, finally, a numerical approach to the solution of the alternating curent and potential distribution in an arbitrary geometry by solution of Laplace's equation is mentioned. The relationship between pore models and macroscopic approaches is outlined. © 1990.