Water management on hydrogen-oxygen proton exchange membrane fuel cell with dead-ended anode and cathode

Dead-ended anode/cathode (DEA/DEC) operation in hydrogen-oxygen fuel cells improves reactant utilization but intensifies water management challenges. In this study, a quasi-two-dimensional model is utilized to investigate the impact of operating condition parameters on cell performance and the distribution of internal liquid water with DEA and DEC. High inlet relative humidity accelerates water flooding and causes voltage degradation, while dry gas extends operating time and reduces system complexity. Elevated temperature promotes water diffusion from the cathode to the anode. However, this also leads to an increase in the vapor pressure of water, which exacerbates concentration losses. Positive pressure difference (where the cathode pressure is higher than the anode pressure) works synergistically with the concentration gradient to drive reverse diffusion of water, preventing membrane drying on the anode side and inhibiting water flooding on the cathode side, resulting in a good water balance. Synergy between pressure difference and concentration gradient becomes the core mechanism of water balance in dead-ended mode, providing a new perspective on cell water management in dead-ended mode. Lower current densities prove essential for stable operation by reducing water generation rates. The results provide valuable guidance for the optimized design of underwater/aerospace fuel cells.