Low-platinum dissymmetric membrane electrode assemblies for fuel cells suitable for a variety of external humidification conditions

Electrospun fuel cell catalyst layers have been shown to significantly reduce Pt consumption; however, obvious performance degradation often occurs under low external humidification conditions. To overcome this problem, we propose a novel dissymmetric membrane electrode assembly (MEA) that contains a graded pore gas diffusion anode and an electrospun cathode catalyst layer (CCL). The microporous layer containing hydrophilic ionomer has a similar structure as the anode catalyst layer, which improves water management and alleviates the effects of both water flooding and drying on the performance of the MEA. With the high Pt utilization of the electrospun CCL, the total Pt consumption of the MEA is 0.124 g kW−1 (H2/air, 100% RH) and successfully reaches the U.S. Department of Energy 2020 target. Even if the external humidification conditions are reduced to harsh 30%anode/0%cathode RH, the total Pt consumption of the MEA is only 0.156 g kW−1, which is significantly better than current conventional MEAs. In addition, the cathode and anode in this novel dissymmetric MEA can be fabricated separately, and no substrates have to be flipped over during the fabrication process, which reduce the production difficulty and rejection rate, and are beneficial to flow-line production.