Wet Mechanochemical Synthesis of BH4‐Substituted Lithium Argyrodites

Abstract

AbstractIn all‐solid‐state batteries, a solid electrolyte with high ionic conductivity is required for fast charging, uniform lithium deposition, and increased cathode capacity. Lithium argyrodite with BH4− substitution has promising potential due to its higher ionic conductivity compared to argyrodites substituted with halides. In this study, Li5.25PS4.25(BH4)1.75, characterized by a high ionic conductivity of 13.8 mS cm−1 at 25 °C, is synthesized via wet ball‐milling employing o‐xylene. The investigation focused on optimizing wet ball‐milling parameters such as ball size, xylene content, drying temperature, as well as the amount of BH4− substitution in argyrodite. An all‐solid‐state battery prepared using Li5.25PS4.25(BH4)1.75 as the electrolyte and LiNbO3 coated NCM811 as the cathode exhibits an initial coulombic efficiency of 90.2% and maintains 93.9% of its initial capacity after 100 cycles at fast charging rate (5C). It is anticipated that the application of this wet mechanochemical synthesis will contribute further to the commercialization of all‐solid‐state batteries using BH4‐substituted argyrodites.