Tuning the Properties of Halide Nanocomposite Solid Electrolytes with Diverse Oxides for All-Solid-State Batteries

Herein, we report halide nanocomposite solid electrolytes (HNSEs) that integrate diverse oxides with alterations that allow tuning of their ionic conductivity, (electro)chemical stability, and specific density. A two-step mechanochemical process enabled the synthesis of multimetal (or nonmetal) HNSEs, MO₂-2Li₂ZrCl₆, as verified by pair distribution function and X-ray diffraction analyses. The multimetal (or nonmetal) HNSE strategy increases the ionic conductivity of Li₂ZrCl₆ from 0.40 to 0.82 mS cm^-1. Additionally, cyclic voltammetry test findings corroborated the enhanced passivating properties of the HNSEs. Notably, incorporating SiO₂ into HNSEs leads to a substantial reduction in the specific density of HNSEs, demonstrating their strong potential for achieving a high energy density and lowering costs. Fluorinated SiO₂-2Li₂ZrCl₅F HNSEs exhibited enhanced interfacial compatibility with Li₆PS₅Cl and LiCoO₂ electrodes. Cells employing SiO₂-2Li₂ZrCl₅F with LiCoO₂ exhibit superior electrochemical performance delivering the initial discharge capacity of 162 mA h g^-1 with 93.7% capacity retention at the 100th cycle at 60 °C.