Effects of anisotropic bending stiffness of gas diffusion layer on the MEA degradation of polymer electrolyte membrane fuel cells by wet/dry gas

Abstract

The effects of anisotropic bending stiffness of a gas diffusion layer (GDL) on membrane electrode assembly (MEA) degradation were investigated. We prepared GDLs with a fiber direction perpendicular to the major flow (i.e., “90° GDL”) and with a fiber direction parallel to the major flow (i.e., “0° GDL”). To analyze the mechanical durability as a function of GDL anisotropy, we examined cell performances such as the I–V characteristics and impedances and the hydrogen crossover characteristics during wet/dry cycles. The results showed that the 90° GDL fuel cell is superior to the 0° GDL fuel cell in terms of higher I–V performance, lower resistance at high frequency, and lower hydrogen crossover through the MEA. Mechanical degradation of the 0° GDL was investigated using scanning electron microscopy (SEM).