Investigation of Anodic Porous Transport Electrode for Anion Exchange Membrane Electrolyzers

Abstract

As global warming and the exhaustion of fossil fuels deepen, major countries are trying to promote the spread of renewable energy such as solar and wind power. Hydrogen with high energy density, no harmful emissions and various transportation, storage methods is regarded as the optimal energy carrier for renewable energy. Water electrolysis technology is usually used for the transformation of renewable resources to hydrogen. In the development of water electrolysis technology, proton exchange membrane (PEM) water electrolysis used a PEM with high mechanical/chemical stability and a membrane electrode assembly (MEA) with a zero-gap structure of electrodes has excellent variability to power fluctuation and a better electrolysis efficiency. However, due to the acidic electrolyte, cell components materials of PEM water electrolysis are limited to precious metal such as iridium (Ir) based catalysts on anode and platinum-group metals (PGMs) catalyst on cathode. In contrast, in the anion exchange membrane (AEM) water electrolysis, alkaline membrane can be used as electrolyte which means, compared with PEM water electrolysis, widely available non-precious metal catalysts and stainless components can be used. However, different from proton exchange ionomer (PEI), typical models of anion exchange ionomer (AEI) tend to lack mechanical and chemical stabilities and are difficult to apply to the binder for anode catalyst layer [1]. Therefore, we have adopted a different electrode structure for each of the two electrodes in the MEA, that is, catalyst-coated-membrane (CCM) for the cathode and porous transport electrode (PTE) for the anode.In this study, various types of PTE were fabricated and applied for the anode. The effect of each property of PTE (catalyst lading, porosity, thickness, and pore diameter) on the electrolysis performance was examined experimentally.AcknowledgementPart of the experiments reported here are supported by the New Energy and Industrial Technology Development Organization (NEDO).Reference[1] H. Ito et al. J. Appl. Electrochem., 48, 305 (2018)