Property evolution of gas diffusion layer and performance shrink of fuel cell during operation

The last decade has seen a renewed emphasis on proton exchange membrane fuel cells. As an essential component in proton exchange membrane fuel cells, gas diffusion layer assumes significant responsibility on water management, as well as on the performance and durability of proton exchange membrane fuel cells. However, researchers have not determined what is the relationship between gas diffusion layer characteristic evolution and the mass transport shrink in proton exchange membrane fuel cells during operation. The objective of this study is to investigate how the property of the gas diffusion layer evolves during cell operation and its relationship with the mass transport of the stack. The results showed that the hydrophilicity of the gas diffusion layer surface and bulk phase increased obviously after the endurance test. The loss of hydrophobic agents and the exposure of hydrophilic surfaces are mainly responsible for this phenomenon. In addition, the structural collapse severely damages the mechanical strength of the gas diffusion layer and thus hinders the electrical conductivity and mass transfer capability of the gas diffusion layer. Loss of hydrophobicity and mechanical strength cause a serious decline in the performance of proton exchange membrane fuel cells.