Abstract
Self diffusion coefficients of water in polymer electrolyte fuel cell membrane(PEM) were measured using pulsed field gradient spin echo NMR measurement. Two types of PEM sample were investigated at various water content. It is shown that measured self-diffusion coefficients increased with water content in the membane, although no distinct difference was observed among two types of PEM. Furthermore, it is demonstrated that NMR imaging technique can be applied to probe water behaviors in PEM assembled in fuel cell under operation. It is shown that PEM gradually dried after the fuel cell began to be operated, resulting in decreasing output current.
