Investigation of Durability of MEAs at Higher Temperature

Abstract

For the next generation polymer electrolyte fuel cell (PEFC), increase in operating temperature above 100 °C is desired in order to improve the cathode overvoltage. The objective of this study is to understand degradation phenomena of cathode catalysts by simulating Fuel Cell Vehicle’s “load cycles”, where Pt dissolution/reprecipitation reaction occurs. Standard membrane-electrode-assemblies (MEAs) made with Nafion ® membrane were evaluated under increased temperature like 105 °C and also under reduced humidity condition like RH57%. As a result, comparing to the standard operating condition (80 °C and RH100%), Pt enlargement was suppressed at RH57% owing to the presence of smaller amount of water. However, degradation of Nafion ® ionomer under low humidity condition led to lowering MEA performance. Furthermore, at higher temperature, in addition to Nafion ® degradation, enhanced Pt enlargement was recognized and became a serious problem on MEA performance.