EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

In recent years, ternary halides Li3MX6 (M = Y, Er, In; X = Cl, Br, I) have garnered attention as solid-state battery material due to their high electrochemical stabilities and room-temperature conductivities. In this material class, the influences of isovalent or aliovalent substitutions are rarely studied despite being a common tool for correlating structure and transport properties. This work presents an investigation on the impact of Zr-substitution on the structure and ionic conductivity of Li3InCl6 (Li3-xIn1-xZrxCl6 with x = 0 - 0.5) using a combination of X-ray diffraction, neutron diffraction, bond valence sum calculations and potentiostatic impedance spectroscopy. Analysis of high-resolution diffraction data confirms presence of an additional tetrahedrally coordinated lithium position along with metal-lithium site-disorder which were not reported in the previous data of Li3InCl6. This leads to formation of a three-dimensional lithium diffusion channel which was further supported by bond valence sum calculations. Upon Zr substitution, the structure exhibited asymmetric volume changes along with an increasing number of vacancies, which internally leads to rise the room temperature ionic conductivity from 0.46 mS∙cm-1 to 1.24 mS∙cm-1 for x = 0.4 showing a strong influence of the Li-ion density on the ionic transport of halide electrolytes.