In-situ diagnosis of state-of-health inconsistency in membrane electrode assembly components within proton exchange membrane electrolyser stacks with high catalytic compatibility

Large-scale proton exchange membrane (PEM) electrolyser stacks have advanced significantly in recent years. Integrating PEM electrolyser stacks with renewable energy for hydrogen production enhances renewable energy utilization, reduces global warming, and supports global energy and economic sustainability. However, performance inconsistencies among individual membrane electrode assemblies (MEAs) within the PEM electrolyser stacks, coupled with challenges of conducting in-situ evaluations, increase maintenance costs and reduce economic efficiency. This study proposes an advanced micro-current excitation analytical method for in-situ parameter acquisition of individual MEAs in PEM electrolyser stacks. For catalysts lacking hydrogen adsorption/desorption (HAD) processes (e.g., IrO2), hydrogen crossover current density, double-layer capacitance, and ohmic resistance are obtained, and for HAD-capable catalysts like Ir black, it also measures the integrated net charge for hydrogen desorption. Method validation was performed through comparative testing against established techniques, including linear sweep voltammetry and cyclic voltammetry. Additionally, the effects of operating conditions (temperature and cathode back pressure) on MEA parameters were investigated. The findings show that an increase in stack temperature and cathode back pressure enhances iH, while higher stack temperature increases Cdl. Finally, we employed this method to evaluate the inconsistency of the 5-cell PEM electrolyser stacks equipped with Ir black or IrO2, thereby establishing correlations between cell performance and MEA parameters. This method is expected to serve as a critical in-situ diagnostic tool for PEM electrolyser stacks inconsistency evaluation across diverse catalyst types, thereby helping to diagnose the health of MEAs and reduce maintenance costs.