High-performance and durable membrane electrode assemblies based on CeO2 and ePTFE double-reinforcement strategy for proton exchange membrane fuel cells operating at elevated temperatures

The membrane electrode assemblies (MEAs) play a decisive role in operating conditions and lifetime of fuel cell. In this study, MEAs that could work stably at elevated temperatures were prepared. With this method, a shortside chain perfluorosulfonic acid ionomer coating with CeO2 nanoparticles and two layers of expanded polytetrafluoroethylene reinforcement, to be used as a proton exchange membrane, was directly deposited between the cathode and anode gas diffusion electrodes, forming a double-reinforced integrated MEA. The effects of CeO2 doping amount on performance and other electrochemical properties of MEAs were systematically studied. Under the coupling effect of the water-retention and non-proton-conducting properties of CeO2, the 0.5 wt% CeO2-doped MEA (MEA-S0.5) had optimal performance above 100 degrees C and under low relative humidity (RH) conditions. At 120 degrees C and 30% RH, MEA-S0.5 exhibited peak power density of 0.460 W cm-2 (H2/air operation, 100 kPa), which was about 1.28 times that of MEA without CeO2 doping (MEA-S0). Furthermore, CeO2 effectively enhanced the durability of the MEA. Compared with MEA-S0, MEA-S0.5 did not exhibit significant degradation in output power, H2 crossover, or proton conductivity in the 100-h open-circuit voltage-holding test. This work paves the way for developing high-performance, durable MEAs that are suitable for elevated temperatures.