A novel gradient double-sided rectangular blockage cathode flow field for enhancing mass transport and output performance in PEMFCs

To enhance hydrogen fuel utilization and power density in proton exchange membrane fuel cells, persistent challenges in water management and efficient reactant transport at the cathode must be addressed. This study introduces and validates a novel gradient double-sided rectangular blockage flow field through a systematic methodology integrating experimental screening, numerical multi-objective optimization, and final experimental validation. Initial experiments evaluated various blockage geometries (triangular, rectangular, trapezoidal, and circular), identifying the rectangular profile as optimal for mass transport enhancement due to its vertical windward face. Multi-objective optimization determined the optimal blockage parameters (0.35 mm width, 0.6535 mm average height and the 0.0404 mm height increment), with experimental validation confirming that this design yields an 11.28 % enhancement compared to the traditional parallel channel. Numerical simulations validated enhanced reactant distribution and water management, with a 19.34 % increase in average oxygen concentration at the MPL/CL interface, a 13.64 % reduction in oxygen non-uniformity, improved water drainage from porous media, and preserved hydration in proton-conducting regions. The proposed cathode flow field provides a reliable approach to enhance reactant transport efficiency and address water management issues, offering a promising solution for next-generation high performance fuel cells.