Permeation Process for Reaction Species in A Gas Diffusible Non-Porous Polymer Electrode

Abstract

A hybrid polymer film composed of cobalt phthalocyanine (Co-Pc), carbon black and a binder polymer was prepared and used as a gas diffusion electrode for the electrochemical reduction of oxygen in an alkaline solution. Four kinds of polymers with different gas permeability were chosen as the binder polymer. In order to clarify the permeation pathway of the reaction species in a non-porous film electrode, the relationship between the permeability of oxygen or water vapor and the electrode activity in the diffusion rate determining process was investigated for the film electrodes. From the temperature dependence of the oxygen permeability (dry), the film electrode was confirmed as a non-porous film. It was found that the oxygen permeability of the film electrode was fairly dependent on the kinds of binder polymers used, and effected on the critical current density (Ic) of the electrode. In the case of using the film electrodes with various amounts of binder polymer, the electrode activity was influenced by the permeation rate of water vapor. The permeation pathway for the reaction species in the non-porous film electrode was discussed on the basis of these results.