Microstructure Characterization of Nafion® HP JP as a Proton Exchange Membrane for Fuel Cell: Positron Annihilation Study
Hamdy F.M. Mohameda,b, E.E. Abdel-Hady a, M.O. Abdel-Hamed a and M. Said a
aPhysics Department, Faculty of Science, Minia University, P.O. Box 61519 Minia, Egypt
bRenewable Energy Science & Engineering Department, Faculty of Postgraduate Studies for Advanced Science (PSAS), Beni-Suef University, P.O. Box 62511 Beni-Suef, Egypt
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Free volume size Vf and proton conductivity σ of a novel polymer electrolyte membrane were investigated as a function of temperature and relative humidity up to 140°C and 80%, respectively. The free volume size Vf for Nafion® HP JP reflect the α-transition temperature at about 98°C. In addition the free volume size Vf for Nafion® HP JP is smaller than that for Nafion® NRE212 membrane which leads to lower methanol permeability of the former membrane. The proton conductivity σ for Nafion® HP JP decreases with increase of temperature up to transition temperature due to free and bound water loss, then it starts to increase due to dynamic segmental motion. It increases for Nafion® HP JP with the increase of the relative humidity. A good correlation between Vf and σ was successfully established for both membranes which indicates that σ is governed by the free volume. In conclusion, Nafion® HP JP is a suitable membrane for a proton exchange membrane fuel cell application.

DOI: 10.12693/APhysPolA.132.1543
PACS numbers: 78.70.Bj, 82.47.Nj, 72.80.Le, 36.10.Dr, 88.30.J-, 88.30.pf