High Performance Anion Exchange Membrane Electrolysis using Plasma-Sprayed, Non-Precious Metal Electrodes

Abstract

The production of green hydrogen by a cost-effective electrolysis technology is of paramount importance for future energy supply systems. In this regard, proton exchange membrane (PEM) electrolysis is the technology of choice due to its compactness and high efficiency, however its dependence on the scarce iridium catalyst jeopardizes the deployment at large scale. Here, we present a low cost electrolyzer consisting of an assembly of an anion exchange membrane (AEM) and plasma-sprayed electrodes without any precious metals. Several electrode materials are developed and tested in this configuration at 60 C and feeding 1M KOH electrolyte. The AEM electrolyzer with NiAlMo electrodes is able to achieve a potential of 2.086 V at a current density of 2 A cm-2, which is comparable to the performances of industrial MW-size PEM electrolyzers. The cell potential with NiAl anode and NiAlMo cathode is 0.4 V higher at the same current density, but it keeps a stable operation for more than 150 h. Through different post-mortem analyses on the aged electrodes, the degradation mechanism of NiAlMo anode is elucidated. The efficiencies of the developed AEM electrolyzer concept reported herein are close to those of the commercial PEM systems, and thus a cost-effective alternative to this technology is provided based on our results.