Stable Interface Chemistry and Multiple Ion Transport of Composite Electrolyte Contribute to Ultra‐long Cycling Solid‐State LiNi0.8Co0.1Mn0.1O2/Lithium Metal Batteries

Abstract Severe interfacial side reactions of polymer electrolyte with LiNi 0.8 Co 0.1 Mn 0.1 O 2 (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 (PO 4 ) 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.