Enabling Scalable Polymer Electrolyte with Dual‐Reinforced Stable Interface for 4.5 V Lithium‐Metal Batteries

Abstract Hitherto, it remains a great challenge to stabilize electrolyte–electrode interfaces and impede lithium dendrite proliferation in lithium‐metal batteries with high‐capacity nickel‐rich LiN x Co y Mn 1− x−y O 2 (NCM) layer cathodes. Herein, a special molecular‐level‐designed polymer electrolyte is prepared by the copolymerization of hexafluorobutyl acrylate and methylene bisacrylamide to construct dual‐reinforced stable interfaces. Verified by X‐ray photoelectron spectroscopy depth profiling, there are favorable solid electrolyte interphase (SEI) layers on Li metal anodes and robust cathode electrolyte interphase (CEI) on Ni‐rich cathodes. The SEI enriched in lithiophilic N−(C) 3 guides the homogenous distribution of Li + and facilitates the transport of Li + through LiF and Li 3 N, promoting uniform Li + plating and stripping. Moreover, the CEI with antioxidative amide groups can suppress the parasitic reactions between cathode and electrolyte and the structural degradation of cathode. Meanwhile, a unique two‐stage rheology‐tuning UV polymerization strategy is utilized, which is quite suited for continuous electrolyte fabrication with environmental friendliness. The fabricated polymer electrolyte exhibits a high ionic conductivity of 1.01 mS cm −1 at room temperature. 4.5 V NCM622//Li batteries achieve prolonged operation with a retention rate of 85.0% after 500 cycles at 0.5 C. This work provides new insights into molecular design and processibility design for polymer‐based high‐voltage batteries.