2022 Volume 90 Issue 12 Pages 127002
Polymer electrolyte membrane (PEM) water electrolysis has received significant attention as a suitable technology for hydrogen production because it can operate at a high current density, is compact, and can produce high purity hydrogen. However, this process involves high costs because precious metal catalysts are required to maintain high performance. To overcome this challenge and develop new materials to replace precious metals, the complex overlapping overpotentials must be considered separately. In a previous study, a structure that uses double reference electrodes by shifting the electrode arrangement was proposed for separating the overpotentials. This structure allows the electrolyte surface potential to be measured by a reference electrode far from the electrode by changing the potential distribution. However, the structure may cause a complicated three-dimensional potential distribution, which may adversely affects accurate measurement of the electrode potential. Therefore, the potential distribution was analyzed and evaluated using three-dimensional multiphysics simulations incorporating proton and electron conduction. As a result, a remarkable phenomenon called potential wraparound, which affects the distribution of electric potential, was observed. Furthermore, a significant finding was that this effect can be suppressed by changing the shape of the electrode.
