Wet Mechanochemical Synthesis of BH 4 -Substituted Lithium Argyrodites.

In 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 BH 4 - substitution has promising potential due to its higher ionic conductivity compared to argyrodites substituted with halides. In this study, Li 5.25 PS 4.25 (BH 4 ) 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 BH 4 - substitution in argyrodite. An all-solid-state battery prepared using Li 5.25 PS 4.25 (BH 4 ) 1.75 as the electrolyte and LiNbO 3 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 BH 4 -substituted argyrodites.