High tempreture fuel cell performance and anisotropy of carbonyl and sulfone groups co-crosslinked sulfonated polyimides proton exchange membranes

Anisotropic properties of membrane swelling and proton conductivity of carbonyl and sulfone groups co-crosslinked sulfonated polyimides(SPI) proton exchange membranes(M1C, M2C) were reported in this paper. Fuel cell performance and durability under high temperature and relative low humidification were investigated in detail. The results showed that dimensional changes of M1C and M2C were lower than that of sulfone group crosslinked R1C in thickness and no obviously change in plane direction. The through-plane proton conductivities of M1C and M2C were significantly larger than that of R1C. The operation conditions of temperature, back pressureand relative humidity largely affected the proton exchange membrames of fuel cell(PEMFC) performance in connection with each other. The PEMFC performance of M1C was better than that of R1C in the similar conditions. At 90℃ and relatively high humidification of 82%RH, the crosslinked PEMs showed high fuel cell performances which were comparable to NR212. As the humidification reduced to 27% RH, the fuel cell performance of M1C largely decreased, but still kept in a reasonably high level and higher than that of R1C. With the operation temperature increased from 90℃ to 110℃, cell performances of all the SPI PEMs decreasedlargely. At 0.2 MPa and 49%RH, the maximum output of M1C was 21% higher than R1C. The maximum output of M1C largely increased from 0.17 W/cm² at 0.2 MPa to 0.38 W/cm² at 0.3 MPa. The PEMFC with M1C operated at 110℃ for 330 h without obviously degradation in cell performance. The result indicated that carbonyl and sulfone groups co-crosslinked SPI PEMs have high temperature fuel cell durability.