Synthesis and physical properties of proton conductors, A-

Fuel cells operating at medium temperature range from 473 to 773 K have attracted worldwide attentions for the applications as clean power sources for automobiles and co-generation systems. Solid electrolyte is a key issue to the development of the devices, which are able to work in the medium temperature range. Among the electrolyte proposed for this temperature range, solid acids are believed to be one of the most promising materials [1, 2]. CsH2PO4 and CsHSO4 are well known as high proton conductors. The ionic conductivity exceeds 10-2 Scm-1 at 200°C. However, the temperature range where the material shows high proton conduction is rather narrow, and the search for new proton conductors is still necessary. We have been investigated new proto