Effect of sintering temperature on the structural, electrical and electrochemical properties of novel Mg0.5Si2 (PO4)3 ceramic electrolytes

The objective of the present study is to investigate the effect of sintering temperature on the structural, electrical and electrochemical properties of novel Mg0.5Si2 (PO4) 3 NASICON structured compound prepared via sol gel method. X-ray diffraction was used to study the structural properties such as crystalline phase and lattice parameters of the solid electrolytes. Electrical properties of the compound were measured using impedance spectroscopy while the electrochemical stability was investigated by linear sweep voltammetry. All the sintering temperatures yielded compounds consisted of monoclinic crystalline phase with a space group of P1 21/c1. Lattice parameters for Mg0.5Si2 (PO4) 3 samples increased from the sintering temperature at 700–800 °C but decreased for sintering temperature at 900 °C. The sample sintered at 800 °C showed the highest total conductivity of 1.83×10−5 S cm−1 and the highest value of ions mobility, µ of 6.17×1010 cm2 V−1 s−1 which was attributed to the optimum size of migration channel indicated by its unit cell volume. Linear sweep voltammetry result showed that the Mg0.5Si2 (PO4)3 powder was electrochemically stable up to 3.21 V.