Microscale structure optimization of catalyst layer for comprehensive performance enhancement in proton exchange membrane fuel cell

Abstract

The catalyst layer plays a significant role in promoting the redox reaction of proton exchange membrane fuel cells (PEMFC). Especially at high current densities, as the oxygen reduction rate increases and more water is produced, the pores of the catalyst layer are easily clogged, thus preventing the oxygen from reaching the reactive sites. In this work, a cathode catalyst layer with micro-grooved structure is proposed to optimize the water-gas transport and output performance of PEMFC. Three-dimensional two-phase numerical simulation results show that the catalyst layer with grooves significantly improves the water-gas transport performance of PEMFC, with a maximum increase of 4.76 % in output performance. Combining the response surface methodology and non-dominated sorting genetic algorithm-II for multi-objective optimization (MOO), the optimal solution corresponding to anode/cathode relative humidity and ionomer volume fraction is confirmed to be 86.73 %, 80.10 %, and 0.2592, respectively. The optimization objectives (oxygen concentration, liquid saturation, and net power density) are improved by 3.88 %, 1.95 %, and 1.79 %, respectively. The differences between the three optimization objectives obtained by numerical simulation verification are only 0.61 %, 0.32 %, and 0.55 %, indicating that the MOO results are reliable and accurate.