Parametric study of PEM water electrolyzer performance

Green hydrogen can contribute significantly to combating climate change by helping to establish an energy economy that is both sustainable and carbon-free. One pathway to obtaining green hydrogen is by water electrolysis powered by renewable energy. Proton exchange membrane water electrolysis (PEMWE) is a promising option owing to its high current density at high efficiency. Here, we report on experimental results from a parametric investigation of PEMWE. We have examined the effect of water flow rate at 80 degrees C using a 5 cm2 PEM electrolyzer cell hardware and lab-fabricated membrane electrode assemblies. The results showed that a water flow rate of 0.08 ml cm-2 min-1 was sufficient to meet the water consumption by electrochemical reactions at the anode as well as water depletion by diffusion and electroosmotic drag. We then employed this optimal flow rate to examine the effect of various operating parameters on PEMWE performance and efficiency such as operating temperature, membrane thickness, flow field channel configuration, and porous transport layers as a function of the applied voltage. The results provide useful insights into the operating conditions for optimal PEMWE performance.