Modulating Lithium-Ion Transport in LiAlBr via S-Modified Anion Sublattice.

Tailoring the structures or chemical compositions of the host lattice modulates cation-anion interactions, enhancing active cation transport. Herein, a Br-S mixed-anion sublattice in LiAlBr lowers the migration energy barrier, facilitating lithium redistribution, and enhanced ionic conductivity in LiAlBrS. Ab initio molecular dynamics simulations reveal restricted diffusion in LiAlBr, whereas LiAlBrS features a delocalized network indicative of improved macroscopic Li transport. LiAlBrS exhibits excellent cycling stability and rate capability in all-solid-state batteries, delivering a high specific capacity of 150.2 mAh g at 2C in a Li-In|LiPSCl|2(LiAlBrS): TiS cell, outperforming the LiAlBr-based system (45.2 mAh g) under the same conditions. These findings offer key insights into structure-ion transport relationships, enabling the design of high-performance solid electrolytes.