Investigation of the structure and ionic conductivity of a Li3InCl6 modified by dry room annealing for solid-state Li-ion battery applications

Progress in new sustainable technologies depends on the development of battery materials, specifically on safer, low-cost, and higher energy density batteries. One new type of materials are the halide solid electrolytes (HSEs), which have been shown to exhibit high ionic conductivity, deformability, and oxidative stability. Here, the synthesis of Li3InCl6 (LIC) HSEs by ball-milling followed by dry room annealing is investigated. Crystal structure, particle size, and ionic conductivity are analyzed using a combination of X-ray diffraction, transmission electron microscopy, and electrochemical impedance spectroscopy. Dry room annealing increases the presence of impurities in the sample but also increases the Li+ ionic conductivity up to 1.03 mS cm(-1). Additional pulsed-field gradient and relaxation time NMR measurements were performed to understand the lithium diffusion in the LIC samples. Two-dimensional diffusion - T-2 relaxation correlation and T-2 relaxation exchange measurements showed that there are multiple unique Li atomic motion sites, which are correlated to different rates of diffusive, micrometer-scale motion. This work outlines a simple solid-state synthesis approach and a novel strategy for designing advanced materials, understanding the ionic conduction, as well as the challenges in scalable wet processing of halide-based cathode sheets for solid-state battery applications. (c) 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

Automated summary

Progress in new sustainable technologies relies on the development of battery materials that are safer, low-cost, and have higher energy density. The use of halide solid electrolytes (HSEs) has shown promise due to their high ionic conductivity, deformability, and oxidative stability. This study investigates the synthesis of Li3InCl6 (LIC) HSEs using ball-milling followed by dry room annealing, and analyzes the crystal structure, particle size, and ionic conductivity of the material. The research also explores the lithium diffusion in the LIC samples using pulsed-field gradient and relaxation time NMR measurements.