A comparative study of proton transport properties of zirconium phosphate and its metal exchanged phases

A new phase of amorphous zirconium phosphate (ZrP), an inorganic ion exchanger of the class of tetravalent metal acid (TMA) salt, is synthesized by sol-gel method. The protons present in the structural hydroxyl groups indicate good potential for TMA salts to exhibit solid state proton conduction. Cu²⁺ and Li⁺ are exchanged onto ZrP to yield CuZrP and LiZrP exchanged phases. All these materials were characterized for elemental analysis (ICP-AES), thermal analysis (TGA, DSC), X-ray analysis and FTIR spectroscopy. The transport properties of these materials were explored and compared by measuring conductance at different temperatures using an impedance analyser. It is observed that conductivity decreases with increasing temperature in all cases and mechanism of transportation is proposed to be Grotthuss type. Conductivity performance of ZrP, CuZrP and LiZrP is discussed based on conductivity data and activation energy.