Cl-Doped Cubic\nK<sub>3</sub>SbS<sub>4</sub> as a Solid-State\nElectrolyte for K‑Ion Batteries with Ultrafast Ionic Conductivity

Developing\nhigh-performance solid-state electrolytes (SSEs) is\nof great significance for addressing the foundational scientific issues\nof K-ion batteries and accelerating their transition to practical\napplications. The complex experimental explorations are time-consuming\nand labor-intensive, and the technical barriers in phase synthesis\nhave hindered the development speed of potassium SSEs. In this study,\nwe studied the effect of Cl-doping on the K-ion diffusion rate of\nK<sub>3</sub>SbS<sub>4</sub> via deep molecular dynamics. To reduce\nthe quantum fluctuation phenomena during the simulation process, we\nsimulated a system composed of approximately 3400 atoms for 500 ps\nand averaged the results over five runs. The results of the MD simulation\nshow that Cl doping can induce the generation of potassium vacancies,\nand a small amount of doping can convert K<sub>3</sub>SbS<sub>4</sub> from an ionic insulator to a superionic conductor with an ionic\nconductivity of 14.8 mS/cm at 300 K. The cubic K<sub>3–<i>x</i></sub>SbS<sub>4–<i>x</i></sub>Cl<sub><i>x</i></sub> is a promising candidate for potassium SSEs for\nK-ions.