Degradation study of gas-diffusion layers in proton exchange membrane fuel cell through acid dissolution and oxidation

Durability is one of the key factors influencing the commercialization of fuel cells. Since the gas-diffusion layer (GDL) in fuel cells operates in a high-temperature, high-humidity, acidic environment, performance deterioration occurs over time due to the dissolution and corrosion. This study carried out an aging degradation for 500 h at 80°C in a 1 mol/L H2SO4 and 15% H2O2 solution, and comprehensive experimental investigations were conducted on multiple parameters including the characteristic (thickness, density), mechanical (tensile, cyclic compression), electrical and permeability properties before and after the aging test. It was discovered that the GDL exhibited varying degrees of changes in a range of physicochemical characteristics, including thickness thinning, significant mechanical property attenuation, decreased hydrophobicity, increased electrical conductivity, etc. Microstructural characterization techniques were utilized to investigate the aging morphological features and pore size distributions in order to further explicate these variations. This analysis supports the degradation of the macroscopic physicochemical attributes from the microscopic level. This study is of great practical significance for revealing the durability degradation mechanism of GDL and optimizing the structural design and material screen.