Thermoplastic Elastomeric Bottlebrush Copolymer Glue Electrolyte Featuring Dual-Ion Transport Channels and Strong Segregation: Experimental and Simulation Insights

Abstract

Despite extensive research on electrolytes for energy storage devices, thermoplastic systems that exhibit elasticity, adhesiveness, and nanostructures remain largely unexplored. Herein, a multifunctional thermoplastic elastomeric glue electrolyte is reported based on a poly(vinyl alcohol)-g-poly(2,2,3,3-tetrafluoropropyl methacrylate) (PVA-g-PTFP) bottlebrush copolymer. Grafting superhydrophobic PTFP side chains onto the hydrophilic PVA backbone induces amphiphilic characteristics, facilitating nanoscale-domain formation, controlling crystallinity, and enhancing chain mobility. The high Flory–Huggins interaction parameter (χ = 0.78 at 25 °C) between segments promotes microphase separation and enables dual-ion transport pathways: cations preferentially interact with PVA domains, while anions coordinate within the PTFP-rich domains. Experimental and theoretical analyses confirm the presence of intermolecular interactions, well-organized nanostructures and enhanced ion transport properties. The optimized solid electrolyte exhibits high ionic conductivity, a wide electrochemical stability window, outstanding mechanical elasticity, and notable universal adhesion to diverse surfaces, effectively functioning as an “elastomeric glue electrolyte” enabled by pronounced phase segregation. When used in solid-state supercapacitors, the bottlebrush system achieves significantly higher performance than the neat PVA system and ranks among the top-performing materials reported for activated carbon-based electrodes, even without encapsulation. This showcases a promising strategy to design flexible, high-performance polymer electrolytes via molecular engineering of thermoplastic bottlebrush copolymers.