Reinforced integrated membrane electrode assembly based on ionomer wet-binding and ePTFE reinforcement strategy for proton exchange membrane fuel cells

Abstract

Optimizing the structure of the membrane electrode assembly (MEA) is an effective strategy for improving the performance and durability of proton exchange membrane fuel cells. To prepare reinforced integrated MEAs, in this study, a wet ionomer solution coating with expanded polytetrafluoroethylene (ePTFE) reinforcement was deposited on a cathode gas diffusion electrode (GDE) surface and then wet-binding with the anode GDE. Reinforced integrated MEAs with different layers of ePTFE were prepared and their performance and mechanical durability were compared. The peak power densities of MEAs with single- and double-layer ePTFE reinforcements are 1.26 and 1.19 W cm−2, respectively, which are higher than that of conventional catalyst-coated membrane (CCM)-type MEA (1.04 W cm−2). The common defects in the direct membrane deposition-type MEA, including poor gas barrier ability and mechanical durability of the MEA, are essentially eliminated. The reinforced integrated MEAs have lower degradation than CCM-type MEA in humidity cycling conditions due to the restrictive effect of the ePTFE reinforcement in PEM and the supporting effect of the GDEs on both sides of the PEM. In addition, the double layers of the ePTFE reinforcement endow the MEAs with higher stability and further alleviated the mechanical degradation. The strategy of ionomer wet-binding and multilayered reinforcement provides a novel approach for fabricating MEAs with high performance and mechanical durability.