Halogen-substituted Li3InCl6: Insights into the Evolved Structure, Composition, and Ionic Conductivity

Ternary Li-containing halides have gained significant interest for all-solid-state batteries because they show high Li-ion conductivity, and their structures can be modified. In this study, halogen substitution in Li3InCl6 was attempted to form Li3InCl6–xXx (X = F, Br, I) samples whose phase compositions and Li+ conductivity were characterized by X-ray diffraction and impedance spectroscopy. Based on the evolution of cell parameters, Cl can be substituted completely by F within the experimental limit of x ≤ 1.2, while by other halogens up to a solid solubility limit of x = 0.6 for Br, and x <0.1 for I. The Li-ion conductivity diminished with greater nominal compositions of X in the samples, especially as other phases exhibiting low conductivity are formed. These results suggest that increased polarizability of X is not a dominant factor influencing Li+ mobility in Li3InCl6–xXx.