Sol–gel synthesis and characterization of LiNO3–Al2O3 composite solid electrolyte

Composite solid electrolytes in the system (1 − x)LiNO3–xAl2O3, with x = 0.0–0.5 were synthesized by sol–gel method. The synthesis carried out at low temperature resulted in voluminous and fluffy products. The obtained materials were characterized by X-ray diffraction, differential scanning calorimetry, scanning electron microscopy/energy dispersive X-ray, Fourier transform infrared spectroscopy and AC impedance spectroscopy. Structural analysis of the samples showed base centred cell type of point lattice of LiNO3 for the composite samples with x = 0.1–0.2 and body centred cell for the sample with x = 0.3. A trace amount of α-LiAlO2 crystal phase was also present in these composite samples. The thermal analysis showed that the samples were in a stable phase between 48 °C and 230–260 °C. Morphological analysis indicated the presence of amorphous phase and particles with sizes ranging from micro to nanometre scale for the composite sample with x = 0.1. The conductivities of the composites were in the order of 10−3 and 10−2 S cm−1 at room temperature and 150 °C, respectively.

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