Biomembranes for fuel cell electrolytes employing anhydrous proton-conducting uracil composites

The control of proton transfer through membranes involves 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 membrane fuel cells (PEMFCs) because of the fluidic nature of water, although cell operation above water's boiling point (>100°C) has been considered to provide higher efficiency and easier humidity management. We show that biomembranes consisting of uracil and chitin phosphate have high anhydrous proton conductivities over a wide temperature range, from room temperature to 160°C, with sufficient thermal stability. Water-free conductivities exceeding 10^-3 S/cm have been obtained in the elastic polymeric material, and a fuel cell employing the biomembrane as an electrolyte exhibited stable current generation under non-humidified H₂/O₂ conditions at 160°C.