Novel hydrophobic coating process for gas diffusion layer in PEMFCs

Abstract

The behavior of water and gas distribution in the gas diffusion layers (GDLs) of proton exchange membrane fuel cells (PEMFCs) were investigated analytically. In order to prevent the flooding phenomenon of the electrodes by the product water, gas diffusion layer is usually hydrophobed. Formerly, gas diffusion layer was partially coated with PTFE (polytetrafluroethylene) suspension but flaking-off of PTFE particles were observed. In this study, gas diffusion layer is coated with HTTS ((hepradecafluoro-1,1,2,2-tetrahydrodecyl)triethoxysilane)-derived layers having hydrophobic functional group. The influence of the HTTS coating on gas permeability and hydrophobicity of gas diffusion layer are analyzed and discussed.