Biomembranes for fuel cell electrolytes employing anhydrous proton conducting uracil composites

The controls of proton transfer through membranes involve fundamental properties of chemical energy conversion in industrial devices as well as living systems. In particular, ion-exchange membranes are generally used as superior proton conductors for polymer electrolyte fuel cells (PEFC) due to the fluidic nature of water, although the cell operation above the boiling point (>100 °C) has been considered to provide a higher efficiency and an easier humidity management. We show that biomembranes consisting of uracil and chitin phosphate have large anhydrous proton conductivities over a wide temperature range from room temperature to 160 °C with sufficient thermal stabilities. Water-free conductivities exceeding 10−3 S cm−1 have been obtained in the elastic polymeric material, and the fuel cell employing the biomembrane as an electrolyte exhibited a stable current generation under non-humidified H2/O2 conditions at 160 °C.