| 초록 |
High temperature operating polymer electrolyte membrane fuel cells (PEMFCs) have been studied to decrease anode catalyst poisoning, to improve reaction rate and heat utilization and potentially to simplify fuel cell water management. However, Nafion® based membranes have a problem of poor proton conductivity at high temperature above 100 ℃, leading to high ohmic drop. For better water retention and enhanced proton conductivity at high temperatures, we used a composite membrane of Nafion® with zirconium sulphophenyl phosphate (ZrSPP), Zr(O3PC6H4SO3H)2·nH2O, which maintains high proton conductivity at high temperatures. ZrSPP is typically obtained by the addition of hydrofluoric acid and zirconyl chloride solution into meta-sulphophenyl phosphonic acid. MEA was bonded together by hot-pressing under 80 kg/cm2 at 140 ℃ for 3 min and mounted into a 5 cm2 single cell connnected to a loader (Zahner EL 300). Cell performance was tested at 100 ℃ when the gas humidifier temperature was maintained at 90 ℃ for fuel and 85 ℃ for oxidant gas. The gas flux stoichiometry was fixed at 3.0 for anode and 4.0 for cathode under 30/30 psig.
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