Novel Sol–Gel Synthesis of MgZr4P6O24 Composite Solid Electrolyte and Newer Insight into the Mg2+-Ion Conducting Properties Using Impedance Spectroscopy

Abstract

Magnesium zirconium phosphate, MgZr4P6O24 (MZP), is a magnesium ion conducting ceramic material with potential for application as solid electrolyte in high temperature electrochemical sensor in non-ferrous scrap metal refining and virgin metal alloying operations. In this work, MZP was synthesized using a simple but novel and economical sol–gel route at a significantly reduced temperature. An insight into the calcination process and possible phase transformation at higher temperature was obtained using simultaneous thermogravimetric analysis and differential scanning calorimetry (TGA/DSC). Phase identification of the synthesized material was studied after calcining the powder at 900 °C for 3 h using X-ray diffraction (XRD); a single monoclinic phase was observed at that temperature. However, a trace amount of possible minor second phase, zirconium oxide phosphate [Zr2(PO4)2O], was formed after heating at temperatures T ≥ 1000 °C. Impedance spectroscopy measurements on platinized sintered-MZP pellets were ...