Increase of proton conductivity in amorphous phosphate-Nafion membranes

Fast proton-conducting inorganic-organic hybrids of amorphous phosphate-Nafion (P-Nafion) membranes were found to exhibit appropriate mechanical strength sufficient for measuring their conductivity. In the P-Nafion composite, a drastic increase in proton conductivity up to 4×10-1 S/cm was observed with increasing phosphate concentration. The high proton conductivity may result from an increase in proton density due to the formation of amorphous phosphate networks in Nafion matrix. The increasing water absorption ability due to the incorporation of phosphate also provides high proton mobility, resulting in an increase in proton conductivity.