Anodic microporous layer for polymer electrolyte membrane water electrolysers

摘要

A microporous layer represents an important element of the gas diffusion electrodes used in polymer electrolyte membrane (PEM) fuel cells and water electrolysers. It forms an interface between the nanostructured catalyst layer and the macrostructured electrode body. In the case of PEM water electrolysis such a layer has only been applied to the cathode to date. On the other hand, it is typically absent on the anode side of the cell. In the present study, such a layer was integrated into the anode of a PEM water electrolyser. It was based on antimony-doped tin oxide placed on titanium felt forming the electrode backing. Using an in-house synthesised IrO2, gas diffusion anodes were manufactured with and without the microporous layer and their performance compared in a laboratory PEM water electrolyser. Current-voltage curves and electrochemical impedance spectra were recorded. The results revealed that the microporous layer is only advantageous in a range of low current densities, while at higher current densities the ohmic resistance of the microporous layer significantly reduces the efficiency of electrolysis.