Investigations on lithium carbonate-alumina composite solid electrolyte: Morphology and related conductivity

Abstract

Composite solid electrolytes in the system (1-x)Li 2 CO 3-x Al 2 O3 with x = 0.1 0.6 mole were prepared via sol-gel technique. The morphology and conductivity of the composite were investigated. Obtained materials were analysed by X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, Fourier transform infrared spectroscopy and chemical constituents were confirmed by energy dispersive X-ray. The ionic conductivity was measured using AC impedance spectroscopy. SEM studies of cross-section morphology clearly showed lithium carbonate crystals became radial fluffy shaped particularly at x = 0.1 and 0.6. Morphological analysis showed homogeneous distribution between Li 2 CO 3 and Al 2 O 3 particles resulted in formation of amorphous phase of Li 2 CO 3 at Li 2 CO 3 - Al 2 O 3 interface. Traces of α-LiAlO 2 , β-LiAlO 2 and LiAl 5 O 8 were observed at x = 0.1, 0.2 and x = 0.4. Impedance spectroscopy studies showed that the conductivity is maximal at x = 0.2 and 0.4 - 0.5 with a value equal to ~10 -3 Scm -1 with temperatures ranging from 130 - 180 °C.