CsH2PO4: Electrolyte for Intermediate Temperature Fuel Cells

This review paper discusses the temperature behavior and thermal event of cesium dihydrogen phosphate (CsH2PO4) in both ambient and high pressure atmosphere. A complete transition from the room-temperature to a high-temperature of CsH2PO4 (monoclinic to cubic phase) occurs between 230 to 240 degrees C, even in the absence of humid conditions and the superprotonic transition precedes the onset of the dehydration/chemical decomposition of the title compound. Decomposition or dehydration can be avoided by either keeping the sample under a H2O-saturated atmosphere, or subjecting the sample to a pressure of 1.0 +/- 0.2 GPa.