An Electrochemical Impedance Spectroscopy Study and Two Phase Flow Analysis of the Anode of Polymer Electrolyte Membrane Water Electrolyser

The effect of water flow rate on the performance of a polymer electrolyte membrane water electrolyser (PEMWE) was studied using an unpressurised lab-scale (25 cm²) cell. The linear polarisation curves obtained showed a voltage increase at higher current densities that increased with water flow rate. Electrochemical impedance spectroscopy (EIS) showed that while lower water flow rates lead to higher cell temperatures and reduced membrane resistance, mass transport losses dominate at high current density. As the water flow is exclusively in the bubbly regime, increase in mass transport limitation is attributed to bubble formation dynamics and reduced gas void fraction at higher water flow rates.