Hydrophilic and Hydrophobic Double MPL Coated GDL to Enhance PEFC Performance under Low and High Humidity Conditions

Abstract

Gas diffusion layers (GDLs) coated with a hydrophobic microporous layer (MPL) have been commonly used to improve the water management properties of polymer electrolyte fuel cells (PEFCs). In the present study, a new hydrophilic and hydrophobic double MPL coated GDL was developed to achieve further enhancement of PEFC performance under both low and high humidity conditions. For the double MPL coated GDLs, the hydrophilic layers using either PVA (polyvinyl alcohol) or TiO2 were coated on the hydrophobic MPL coated GDL. Under low humidity, the double MPLs with the hydrophilic layers using both PVA and TiO2 are effective for conserving humidity at the catalyst layer, thereby enhancing PEFC performance. Under high humidity, because hydrophilicity of the hydrophilic layer using PVA is too high, PEFC performance is deteriorated due to flooding. However, the appropriate hydrophilic layer using TiO2 is effective for reducing flooding, thereby enhancing PEFC performance.