Stable Interface Chemistry and Multiple Ion Transport of Composite Electrolyte Contribute to Ultra‐long Cycling Solid‐State LiNi_0.8Co_0.1Mn_0.1O₂/Lithium Metal Batteries

Abstract

Severe interfacial side reactions of polymer electrolyte with LiNi_0.8 Co_0.1 Mn_0.1 O₂ (NCM811) cathode and Li metal anode restrict the cycling performance of solid-state NCM811/Li batteries. Herein, we propose a chemically stable ceramic-polymer-anchored solvent composite electrolyte with high ionic conductivity of 6.0×10^-4 S cm^-1 , which enables the solid-state NCM811/Li batteries to cycle 1500 times. The Li_1.4 Al_0.4 Ti_1.6 (PO₄ )₃ nanowires (LNs) can tightly anchor the essential N, N-dimethylformamide (DMF) in poly(vinylidene fluoride) (PVDF), greatly enhancing its electrochemical stability and suppressing the side reactions. We identify the ceramic-polymer-liquid multiple ion transport mechanism of the LNs-PVDF-DMF composite electrolyte by tracking the ⁶ Li and ⁷ Li substitution behavior via solid-state NMR. The stable interface chemistry and efficient ion transport of LNs-PVDF-DMF contribute to superior performances of the solid-state batteries at wide temperature range of -20-60 °C.