摘要：

Full cells have been attracting much attention as an alternative source of electricity. Fuel cells use ionomers as proton conducting electrolytes. Recently, our group has developed a new kind of full cell membrane material, sulfonated poly(arylene ether sulfone) copolymers (BPSH) by direct polymerization of sulfonated monomers, which shows good mechanical properties, thermal stability and low methanol permeability with high proton conductivity. Adequate water content in the ionomeric material is essential to maintaining conductivity of the polymer electrolyte membrane. However, excessive amounts of water could impede mass transport within the electrode structures, thereby reducing the mechanical properties of the membranes. A nonuniform water concentration profile is set up in the membrane by an electroosmotic drag of water from anode to cathode and water from cathode to anode. A thorough understanding of water diffusion coefficients in ionomeric membranes is essential for comprehending fuel cell performance.

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