Intermediate-Temperature Fuel Cell Employing CsH[sub 2]PO[sub 4]∕SiP[sub 2]O[sub 7]-Based Composite Electrolytes

The proton-conductive electrolytes based on composites with various molar ratios were synthesized, and their structural and electrochemical properties were investigated at intermediate temperatures. The interfacial chemical reaction between and took place during the heat-treatment at 220°C, resulting in the formation of phase for the composition at . The resulting composites showed high proton conductivity with no conductivity jump inherent in , and the maximum conductivity achieved was at 272°C. The fuel cell employing -based composite electrolyte (molar ratio 1:2, thickness 1.8 mm) was demonstrated at 220°C and showed good performance. It was possible to generate electricity up to , and the maximum power density was .