Investigation on performance of proton exchange membrane electrolyzer with different flow field structures

Proton exchange membrane (PEM) electrolysis provides a sustainable solution for hydrogen generation. As one of the key components, flow field should be properly designed to help distribute reactant evenly across the catalyzed reaction surface area. In this study, three-dimensional models of three flow field structures are built to simulate the internal flow velocity and pressure distribution. The electrolyzer performance of the flow fields at different operating temperature and water pressure is investigated through orthogonal experiments. The output characteristics and electrochemical behavior are investigated by measurement of polarization curves and analysis of electrochemical impedance. It is found that the flow field structure has the most considerable impact on the electrolyzer performance, followed by the operating temperature. The experimental results are consistent with the simulations, indicating that the parallel flow field has lower contact impedance and better mass transfer effect under medium and low current densities due to the large contact area of the channel and the uniform pressure distribution. PEM electrolyzer with the parallel flow field of channel width 1 mm, operating at 60 °C and 0.1 bar anode pressure has the best output performance. Under this condition, the electrolyzer’s potential reaches to 2.1 V at the current density of 1 A/cm2. This work can provide simulation and experimental support for the selection and optimization of PEM electrolyzers’ flow fields and operating conditions.