Incorporating Ionic Liquid 1‐Ethyl‐3‐Methylimidazolium Bromide Into PVA‐LiAc–Based Solid Polymer Electrolytes to Achieve Advanced Solid‐State Lithium‐Ion Batteries

ABSTRACT Solid polymer electrolytes (SPEs) serve as both separators and electrolytes, enhancing the safety of energy storage devices by eliminating liquid components. In this study, we present SPEs prepared from a blend of polyvinyl alcohol (PVA), lithium acetate (LiAc), and the ionic liquid 1‐ethyl‐3‐methylimidazolium bromide ([EMIm]Br). This combination prevents leakage issues common with liquid electrolytes and addresses the low conductivity of typical solid electrolytes. The prepared SPEs are easy to produce, highly transparent, thermally stable up to 271°C, and exhibit high ionic conductivity, with values of 2.21 × 10 −5 S cm −1 when 40% [EMIm]Br is added to the PVA/10% LiAc membrane. Additionally, this composition demonstrates a mechanical strength of 20.40 MPa and an elongation of 485.12%. These findings highlight the strong potential of [EMIm]Br–based SPEs for lithium‐ion batteries.