Characterization of Mg0.5Zr2(PO4)3 for potential use as electrolyte in solid state magnesium batteries

Pure Mg0.5Zr2(PO4)3 which is one of the NASICON-type compounds, was prepared by sol gel method and characterized by X-ray diffraction, Fourier transform infrared analysis, differential scanning calorimetry, scanning electron microscope, energy dispersive X-ray, impedance spectroscopy, magnesium transference number and linear sweep voltammetry techniques. The formation of pure Mg0.5Zr2(PO4)3 compound was obtained at sintering temperature as low as 700 oC. The anion ring in NASICON structure has not been distorted upon switching Li with Mg. The melting temperature of the Mg0.5Zr2(PO4)3 compound was found at temperature 1165 oC. The sample sintered at 750 oC showed the highest total conductivity of 1.0 × 10-6 S cm-1 at ambient temperature and 7.1 × 10-5 S cm-1 at 500 oC. Ionic transference number corresponding to Mg2+ ion transport determined by means of Bruce and Vincent technique was found to be 0.65. Linear sweep voltammetry result showed that the Mg0.5Zr2(PO4)3 electrolyte was electrochemically stable up to 2.50 V versus Mg/Mg2+ electrode and suitable for development of solid electrolytes for magnesium batteries.