Understanding the role of aliovalent cation substitution on the li-ion diffusion mechanism in Li_6+xP_1-xSi_xS₅Br argyrodites.

ABSTRACT: Due to their high ionic conductivity, lithium-ion conducting argyrodites show promise as solid electrolytes for solid-state batteries. Aliovalent substitution is an effective technique to enhance the transport properties of Li₆PS₅Br, where aliovalent Si substitution triples ionic conductivity. However, the origin of this experimentally observed increase is not fully understood. Our density functional theory (DFT) study reveals that Si⁴⁺ substitution increases Li diffusion by activating Li occupancy in the T4 sites. Redistribution of Li-ions within the lattice results in a more uniform distribution of Li around the T4 and neighboring T5 sites, flattening the energy landscape for diffusion. Since the T4 site is positioned in the intercage jump pathway, an inc

SUBMITTER: Schwietert TK 

PROVIDER: S-EPMC10911230 | biostudies-literature | 2024 Mar

REPOSITORIES: biostudies-literature