Structural, Thermal and Conductivity Studies of Magnesium Nitrate – Alumina Composite Solid Electrolytes Prepared via Sol-Gel Method

Abstract

Composite solid electrolytes in the system (1-x)Mg(NO3)2 – xAl2O3 with x = 0.0 – 0.5 were synthesized by a sol-gel method. The synthesis was carried out at a low temperature with magnesium nitrate hexahydrate, as the starting material. The obtained magnesium composite dispersed with alumina were characterized by X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, Fourier transform infrared spectroscopy and alternating current impedance spectroscopy. Structural analysis of the composite samples showed a transformation of the magnesium nitrate hexahydrate crystalline to amorphous magnesium nitrate and magnesium oxide. The composite sample with x = 0.1 and 0.2 exhibited high ionic conductivity of ~10-4 S cm-1 and ~10-6 S cm-1, respectively, at room temperature due to the presence of MgO. This finding offers attractive future composite electrolytes for magnesium-based rechargeable batteries.