Li<sub>9.9</sub>SnP<sub>2</sub>S<sub>11.8</sub>Cl<sub>0.1</sub>O<sub>0.1</sub>: A\nNovel Sulfide Solid-State Electrolyte\nwith High Ionic Conductivity and Air Stability

The high ionic conductivity and favorable mechanical\nproperties\nof sulfide solid-state electrolytes have attracted extensive research\nattention in the field of all-solid-state lithium batteries. However,\nthese materials encounter obstacles related to inadequate air stability\nand limited compatibility with lithium metal. This study prepared\na Cl and O-codoped Li<sub>10</sub>SnP<sub>2</sub>S<sub>12</sub>-type\nsolid-state electrolyte, where the ionic conductivity exhibited a\nnotable enhancement, rising from 1.58 to 2.94 mS cm<sup>–1</sup>. The introduction of Cl can introduce Li vacancies, while codoping\nCl and O can introduce an S–Cl–O mixed anion framework,\nreducing the electrostatic attraction to Li and enlarging the lattice\nvolume. Density functional theory calculations show that the synergistic\nmodulation of Cl and O can reduce the lithium diffusion barrier and\nprovide effective diffusion space. Consequently, this facilitates\na heightened rate of lithium-ion migration, thus elucidating the observed\nenhancement in ionic conductivity. After doping, the electrolyte demonstrates\nenhanced air stability and compatibility with lithium metal. The all-solid-state\nbattery using Li<sub>9.9</sub>SnP<sub>2</sub>S<sub>11.8</sub>Cl<sub>0.1</sub>O<sub>0.1</sub> as the electrolyte shows higher initial\ndischarge specific capacity and good cycling stability.