Achieving an Ultrastable Halide‐Based All‐Solid‐State Lithium Battery via High‐Valent Doping‐Induced s‐p‐d Hybridization

Abstract Halide solid electrolytes (SEs) show great potential in all‐solid‐state batteries (ASSBs) because of their high ionic conductivity and high oxidative stability. But the long‐term cycling stability remains a major concern due to the cathode/halide interface side reactions, especially under high current density. Herein, a s‐p‐d orbital hybridization strategy is proposed via introducing Zr 4+ and F − into Li 3 InCl 6 (LIC‐ZrF 4 ) to regulate the electron localization structure around the central In 3+ . The electron transfer between the cation and Cl is alleviated by the enlarged bandgap (4.485–4.894 eV) with ZrF 4 introduction, and more electrons aggregate around In 3+ after s‐p‐d hybridization among Zr, In, and Cl. This effectively prevents LIC‐ZrF 4 from being attacked by O atoms in LiNi 0 . 8 Co 0 . 1 Mn 0 . 1 (NCM811) and significantly suppresses the interface side reactions. The in situ formed LiF‐containing layer further enhances the interface stability. The assembled ASSB (NCM811/LIC‐ZrF 4 /LPSC/Li‐In) exhibits a state‐of‐the‐art capacity retention (96.7%@500cycles@1C; 80.7%@1600 cycles@2C). Furthermore, the ionic conductivity of LIC‐ZrF 4 is also enhanced from 0.6 to 1.5 mS cm −1 while the electronic conductivity is decreased from 3.66 × 10 −8 to 8.39 × 10 −9 S cm −1 . This work highlights the crucial role of s‐p‐d hybridization on the electron localization regulation and the interface stability, and presents some distinct insights into developing high‐performance halides‐based ASSBs.