Intermediate-temperature fuel cell employing CsH2PO4/SiP2O7-based composite electrolytes

The proton-conductive electrolytes based on CsH2PO4/SiP2O7 composites with various molar ratios were synthesized, and their structural and electrochemical properties were investigated at intermediate temperatures. The interfacial chemical reaction between CsH2PO4 and SiP2O7 took place during the heat-treatment at 220 degrees C, resulting in the formation of CsH5(PO4)(2) phase for the composition at CsH2PO4:SiP2O7 = 2:1 - 1:5. The resulting composites showed high proton conductivity with no conductivity jump inherent in CsH2PO4, and the maximum conductivity achieved was 66 mS cm(-1) at 272 degrees C. The fuel cell employing CsH2PO4/SiP2O7-based composite electrolyte (molar ratio 1:2, thickness 1.8 mm) was demonstrated at 220 degrees C and showed good performance. It was possible to generate electricity up to 150 mA cm(-2), and the maximum power density was 44 mW cm(-2). (c) 2005 The Electrochemical Society. [DOI: 10.1149/1.2142211] All rights reserved.