High-density and low-density gas diffusion layers for proton exchange membrane fuel cells: Comparison of mechanical and transport properties

• Published in: International journal of hydrogen energy 2022-06, Vol.47 (53), p.22532-22544
• Main Authors: Xiao, Liusheng, Bian, Miaoqi, Zhu, Lijun, Duan, Kangjun, Leng, Wenliang, Zeis, Roswitha, Sui, Pang-Chieh, Zhang, Houcheng
• Format: Article
• Language: English
• Subjects: Conductivity measurement; Felt-type GDL; Lattice Boltzmann method; Paper-type GDL; Pore-scale modeling; X-ray computed tomography
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2022.05.092

Gas diffusion layers (GDL) play multi-roles in proton exchange membrane fuel cells, including gas-water transport, thermal-electron conduction and mechanical support. Mechanical strength and transport properties are essential for GDLs. In this work, high-density (paper-type) and low density (felt-type) GDLs are scanned and reconstructed using X-ray computed tomography. Porosities under different compression ratios are compared and discussed. Effective diffusivity and liquid water permeability are calculated using pore-scale modeling and lattice Boltzmann method. Mechanical strength, anisotropic thermal-electrical resistivity for two types of GDLs are obtained using compression tests and thermal-electrical conductivity measurements. Results show that the porosity, diffusivity, permeability, and through-plane thermal-electrical conductivity of felt-type GDL are significantly higher than that of paper-type GDL owing to the higher porosity and fiber-clusters oriented along the through-plane direction. The in-plane electrical resistivity of paper-type GDL is lower than that of felt-type GDL. The mechanical strength of felt-type GDL is much lower, but the fibers of paper-type GDL are more easily to be broken because of its lower elasticity. The results obtained may guide microstructure optimization and performance improvement of GDLs. [Display omitted] •XCT, LBM and PSM are combined to compute porosity, diffusivity and permeability.•SEM and compression tests are applied to investigate the mechanical strength.•Thermal conductivity and electrical resistivity under different compression ratios are measured.•Mechanical and transport properties of two types of GDL are comprehensively compared.