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 solidstate electrolytes were measured using two-probe analysis at a temperature range of 182 -764 o C, and at a frequency within 100 mHz to 32 MHz range. 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 o C and 725 o C, respectively. The sol-gel method was deployed in the synthesis of MgHf4P6O24 and MgZr4P6O24 nanoparticles electrolytes. The thermogravimetric analysis -differential scanning calorimetry (TGA-DSC), and X-ray diffraction (XRD) were characterisation techniques deployed in this study to determine and evaluate the phase composition structure of the nanoparticles calcined at 900 o C and the sample pellets sintered at 1300 o C.