S-p and p-p orbital hybridization induced electronic structure reconfiguration toward manipulating redox behavior of Li-Argyrodite electrolyte for enhanced lithium-compatibility

Abstract

Li-Argyrodite solid electrolytes have shown potential for developing high energy density and safe all-solid-state lithium metal batteries (ASSLMBs) due to the high ionic conductivity and ductile mechanical property. However, the incompatibility of the electrolyte with lithium anode due to the redox decomposition of PS₄³⁻ tetrahedrons inhibits its further application in ASSLMBs. Herein, the redox behavior is manipulated by orbital hybridization induced electronic structure reconfiguration through in-situ electrochemical (de)lithiation of Li_5.5PS_4.5Cl_1.5. The optimized electrolyte with new s-p hybridization of Li-Mg and Mg-S and p-p hybridization of P-S-O not only manipulates the electrons acceptance of PS₄^3- tetrahedrons, but also induces new electron-shielding and lithiophilic phases. The optimized electrolyte therefore shows superior cycling stability of above 2000 h at 0.2 mA cm⁻² with symmetrical lithium electrodes. The all-solid-state batteries with LiFePO₄ and LiNi_0.83Co_0.12Mn_0.05O₂ as cathode display stable cycle performance of 500 and 200 cycles, respectively. This work gains insights into the manipulating mechanism for the redox behavior of Li-argyrodite electrolyte through orbital hybridization, and opens a new route for addressing the lithium anode integration issue of ASSLMBs with high energy density and safety.