Sol-gel Synthesis and Characterization of MgCO3 – Al2O3 Composite Solid Electrolytes

Abstract

Composite solid electrolytes in the system (1-x)MgCO3 – xAl2O3 with x = 0.1 - 0.9 were synthesized by a sol-gel method and analyzed by X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, energy dispersive X-ray, Fourier transform infrared spectroscopy and alternating current impedance spectroscopy for the determination of the phases and crystallinity, thermal stability, surface morphology, elemental composition, chemical bonding and conductivity, respectively. The composites show that, the crystallinity of the composites decreases as the amount of Al2O3 increase which could lead to higher conductivity. The thermal decomposition studies also indicate that the melting and/or decomposition of the composites occur at lower temperature than the pure MgCO3 which normally take place at 350 oC. The composite with the ratio of x = 0.9 give the highest conductivity value in order of 10-4 S.cm-1 as compared to other ratio due to effective transfer of charge carriers in addition to the formation of MgO-Mg2+ species at the interface.