Effect of anode humidity on the performance and current density distribution of PEM fuel cells via experimental and numerical approach

This study employs segmented fuel cells and a high-precision model to investigate the impact of anode humidity on the performance and current density distribution of proton exchange membrane fuel cells (PEMFCs) operating at high current density (2.0 A/cm²) and low stoichiometric ratio (1.5). The results reveal a non-monotonic relationship between anode humidity and fuel cell performance, with optimal performance occurring at approximately 50 % anode humidity. A moderate reduction in anode humidity decreases liquid water saturation in the cathode catalyst layer and membrane water content, thereby enhancing oxygen transport and improving current density uniformity at the cathode outlet. However, excessive reduction in anode humidity leads to membrane dehydration, increasing ohmic resistance and impairing performance. Furthermore, the study demonstrates that the most uniform current density distribution is achieved at 50 % anode humidity, where the standard deviation reaches its minimum. These findings provide valuable insights for optimizing anode humidity to enhance PEMFC performance under high current density conditions.