Improved Ionic Conductivity of MgM4P6O24 (M = Hf, Zr) Ceramic Solid-State Electrolytes by Sol-Gel Synthesis

Abstract

Data from electrochemical impedance measurement of MgHf4P6O24 and MgZr4P6O24 solid-state electrolytes show significant improvement in the ionic conductivity of the ceramic electrolytes. The electrical behaviour of MgHf4P6O24 and MgZr4P6O24 solid-state electrolytes were measured using two-probe analysis at a temperature range of 182-764°C, and at a frequency range within 100 mHz to 32 MHz. In this analysis, promising bulk ionic conductivity of 4.52 x 10-4 Scm-1 and 7.23 x 10-3 Scm-1 were achieved for MgHf4P6O24 and MgZr4P6O24 electrolytes, respectively, at impedance maximum temperatures of 747°C and 725°C, respectively. The sol-gel method was deployed in the synthesis of MgHf4P6O24 and MgZr4P6O24 nanoparticles. The thermogravimetric analysis-differential scanning calorimetry analysis (TGA-DSC), and X-ray diffraction (XRD) characterisation techniques were deployed in this study to determine and evaluate the phase composition structure of the nanoparticles calcined at 900°C and the sample pellets sintered at 1300°C.