Exploring dehydration mechanisms and conductivity optimization in Li3InCl6·xH2O via in situ synchrotron techniques
Journal
Journal of Materials Chemistry A
ISSN
2050-7488
2050-7496
Date Issued
2025
Author(s)
Jheng-Yi Huang
Kevin Iputera
Yen-Ting Lin
Yuan-Ting Hung
Yu-Shuo Liu
Yun-Ping Chang
Behrouz Bazri
Bo-Hong Liu
Da-Hua Wei
Abstract
In recent years, halide solid electrolytes have attracted considerable attention because of their high ionic conductivity and wide electrochemical window. These electrolytes can be prepared as pure phases through a water-based route. However, the mechanism of dehydration reactions in these electrolytes has not been considered thoroughly. This work investigates the dehydration process of lithium indium chloride hydrate (Li3InCl6·xH2O; LIC-xH2O) using a water-mediated method to form lithium indium chloride (Li3InCl6; LIC). The ionic conductivity measurements indicate that an optimal conductivity of 3.2 × 10−4 S cm−1 is achieved at low heating rates and under high-vacuum conditions. In situ synchrotron X-ray diffraction, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy demonstrate that dehydration follows a two-step reaction. The first step involves a solid-solution response with unit cell expansion to remove H2O. The results indicate that high heating rates (above 10 °C min−1) or inert atmospheric conditions lead to the formation of impurities, such as indium oxychloride (InOCl), which hinder ionic conductivity. In contrast, utilizing high-vacuum conditions combined with a slow heating rate enables an optimal dehydration reaction. This approach facilitates the elimination of intermediate phases, which subsequently transform into pure LIC through the progression of the reaction.
Publisher
Royal Society of Chemistry (RSC)
Type
journal article