Water-retention proton exchange membrane assisted with various nanostructures silica

Silicon nanocomposite with various structures was designed to improve the water-retention ability of the proton exchange membrane for elevated temperature performance. The results show that the amorphous SiO2 nanoparticles and SiO2 nanocrystals with size of several nanometers have little influence on the membrane preparation and possess good water-retention of 5.82-7.11 wt% at temperature of 100 degrees C. The mesoporous SiO2/Nafion membrane, however, have large gas crossover of 5.54 mA cm(-2) because of the grain size increase during the crystallinity procedure. The results also demonstrate that the crystallinity of the silica in the membrane significantly increases the water-retention membrane stability. The amorphous SiO2/Nafion membrane has obvious performance decay after a soaked period in water for 20 days with a considerable silicon loss about 25.3%. However, with the crystallinity of the silica, the nanocrystals SiO2/Nafion membrane and the mesoporous SiO2/Nafion membrane have little OCV and power output decrease after the soaking period. The nanocrystals SiO2/Nafion membrane is most favorable PEM because the superiorities of outstanding initial performance and excellent durability. After the soaking period, the maximum power output still can achieve 451 mW/cm(-2) at condition of 100 degrees C and 50 RH%.