Cooperative Transport of Lithium in Disordered Li<sub>10</sub>MP<sub>2</sub>S<sub>12</sub> (M = Sn, Si) Electrolytes for\nLi-Ion Batteries

Disorder\nin sulfide solid-state electrolytes significantly impacts\nchemical bonding, affecting electrochemical properties and interface\nstability. Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub>, a prominent\nsulfide electrolyte, is expensive and has limited interfacial stability,\nso substituting Ge with earth-abundant elements, such as Sn and Si,\ncould be more practical. However, a thorough understanding of the\nkinetics and chemical bonding nature of Li in the Sn/Si-substituted\nsystems is missing owing to the complexity associated with disordered\nsublattice in these materials. We use isothermal–isobaric ensemble\nCar–Parrinello molecular dynamics to evaluate configuration-dependent\ntracer and charged diffusivities and activation energies for lithium-ion\nmigration in disordered configurations of Li<sub>10</sub>SiP<sub>2</sub>S<sub>12</sub> (LSiPS) and Li<sub>10</sub>SnP<sub>2</sub>S<sub>12</sub> (LSnPS) obtained using ensemble statistics. The study uses Li-ion\nprobability density and maximally localized Wannier orbital analysis\nto determine how temperature and Sn and Si cations affect Li-ion migration.\nOur findings indicate that higher temperatures enhance Li-ion mobility\nby enabling more diffusion pathways. The disordered LSiPS and LSnPS\nelectronic structure shows a Kohn–Sham band gap of 2.4 eV for\nLSiPS and 2 eV for LSnPS, of the most probable configuration across\n500 configurations, suggesting a wider electrolyte window for LSiPS.\nAdditionally, Wannier function visualizations demonstrated the significant\nimpact of locality and temperature on the dynamic nature of bonding\nstates of migrating Li ions.