Structural, thermal, and transport properties of nanocomposite CsH2PO4/NaH2PO4/TiO2: A novel proton conducting electrolyte for fuel cells

Abstract

The composites of CsH2PO4/NaH2PO4/TiO2 were prepared by chemical route. The structural, thermal, and conductive properties were investigated by X-ray diffraction analysis, thermal analysis, and conductivity measurements, respectively. CsH2PO4 shows a superprotonic phase transition from the monoclinic to the cubic phase at 230 °C at which the conductivity increases by four orders of magnitude. The initial dehydration event that occurred in CsH2PO4 was observed at 250 °C and the dehydration behavior also decreased at high temperatures due to the additives. The performance of CsH2PO4 was improved based on conductivity and stability by adding TiO2 and NaH2PO4. 5CsH2PO4/3NaH2PO4/2TiO2 and 6CsH2PO4/2NaH2PO4/2TiO2 were found to have the lowest weight loss compared to other composites. The conductivity also increases up to 1.5 orders of magnitude at lower temperatures. The conductivity was found to be highest for the composite 8CsH2PO4/1NaH2PO4/1TiO2 with a value of 1.4 × 10−2 S cm−1.