Preparation and characterization of mixed halide systems as solid electrolyte base

Abstract

The preparations of mixed halide matrices KCl:NaCl and BaCl₂:KCl and the effect of ionic size and valency difference of cations on the ionic conductivity of mixed halides are reported in this paper. The ionic conductivities of mixed halide matrices [(KCl)_{(1 - x)}:(NaCl)_x; 0≤x≤0.4] and [(BaCl₂)_{(1 - y)}:(KCl)_y; 0≤y≤0.5] have been investigated by impedance spectroscopy method. The compositions (KCl)_0.9:(NaCl)_0.1and (BaCl₂)_0.9:(KCl)_0.1 are found to be highly conducting. The thermal characterizations by TG and DTA of the samples of highly conducting compositions have shown no evidence of new compound formation. A simple model based on the wrong size substitution has been applied to understand conductivity enhancement in the mixed matrices. In the case of (BaCl₂)_0.9:(KCl)_0.1, the conductivity enhancement could be attributed to the net charge transfer across the interface of the biphasic mixture. However, for the (KCl)_0.9:(NaCl)_0.1system, the wrong ionic size plays a significant role in the conductivity enhancement.