Collaborative Design of Multi‐Molecules Boosts the Performance of the Full‐Range Three‐Dimensional Quasi‐Solid Polymer Electrolyte for Lithium Metal Batteries

Abstract Solid polymer electrolytes, known for their ease of processing and excellent interfacial contact, play a crucial role in developing high‐energy‐density lithium metal batteries. To address the limitations of single‐function polymer electrolytes such as polyethylene oxide and polyacrylonitrile, it's imperative to develop polymer electrolytes with superior comprehensive performance by incorporating functional organic molecules. In this study, a quasi‐solid polymer electrolyte named VAPE is prepared using a multivariate molecular synergistic strategy. This approach integrates vinyl acetate (VAC), acrylonitrile (AN), and trimethylolpropane ethoxylate triacylate (ETPTA) into a full‐range, 3D cross‐linked network via radical‐initiated polymerization. The cross‐linked structure and the synergistic effect of multiple functional units accelerate the lithium‐ion transport kinetics of VAPE and induce the formation of dense and stable solid‐electrolyte interphase and cathode‐electrolyte interphase layers. As a result, the assembled Li/VAPE₁₃/Li symmetric cell exhibits stable cycling for over 800 h. Furthermore, the terpolymer electrolyte VAPE₁₃ demonstrates an electrochemical window up to 5.30 V. Therefore, the LiNi_0.8Mn_0.1Co_0.1O₂ (NCM811)/VAPE₁₃/Li battery displays excellent cycling stability with 80% capacity retention after 350 cycles at 0.5C. Even at the ultra‐high cut‐off voltage of 4.7 V, the NCM811/VAPE₁₃/Li battery achieves a capacity retention rate of 84.8% after 100 cycles at 0.2C.