All-solid-state proton conductive membranes prepared by a semi-interpenetrating polymer network (semi-IPN)

Novel all-solid-state ion conductive polymer membranes were synthesized for anhydrous high temperature fuel cells. Ion-conductive monomers (ethylene glycol methacrylate phosphates, phosmers) were employed for fixing ion-conductive moieties in the matrix polymer (sulfonated poly(arylene sulfone), sPAS). Inorganic materials, acid-doped titanium oxide and tin indium phosphate were introduced to form anhydrous polymer composite membranes. As a result, poly(phosmer)s significantly improved both the proton conductivity and flexibility of the composite membranes. Sulfonated poly(arylene sulfone)-poly(phosmer)-tin indium phosphate composite membranes showed the highest ion-conductivity value under anhydrous conditions due to the dipolar interaction of poly(phosmer) with the matrix polymer and the inorganic material. The composite membranes exhibited a drastic enhancement in performances of anhydrous high temperature fuel cells compared to those of Nafion-based composite membranes. The fuel cell performances indicate that the poly(arylene sulfone)-poly(phosmer)-inorganic particle composites could be applicable for anhydrous high temperature fuel cells as promising polymer electrolyte membranes.This work was supported by a grant (223-111-002) from the Converging Technology Project of Korea Institute of Environment Science and Technology (KIEST) funded by Korea Ministry of Environment. We also wish to thank Dr Tae Young Kim and Dr Pilwon Heo for FC cell test and kind supply of SIPO