Network‐Driven Ion Transport in Robust In Situ Polymerized Electrolyte‐Integrated Cathodes for Long‐Life Structural Batteries in Intelligent Sensing Platforms

The limited cycle life of solid-state lithium-ion batteries is largely attributed to the low ionic conductivity and poor mechanical strength of solid electrolytes, as well as unstable electrode/electrolyte interfaces. Herein, a solid-state electrolyte synthesized via in situ polymerization of bisphenol A ethoxylate dimethacrylate (E2BADMA) and poly(ethylene oxide) diacrylate (PEGDA) in LiTFSI-carbonate-based electrolytes is reported, achieving high ionic conductivity and mechanical robustness. By combining density functional theory (DFT) simulations and experimental validation, a previously unidentified network-enhanced transport mechanism is uncovered, whereby the poly(E2BADMA) chains not only enhance mechanical integrity but also introduce abundant active sites for Li⁺ transport. Leveraging these properties, an integrated solid electrolyte/cathode architecture with excellent electrochemical performance and high stiffness is constructed. When incorporated into full cells, the electrolyte facilitates the formation of robust electrode/electrolyte interfaces, significantly improving their interfacial stability and enabling long-term cycling. The resulting solid-state lithium-ion batteries display stable performance over 300 cycles with negligible capacity fading. Moreover, the solid electrolyte enables the development of structural batteries which retain ≈100 mAh g^-1 after 120 cycles. When deployed as load-bearing elements in a conceptual electric vehicle frame, these structural batteries reliably power movable platforms and multiple sensors, showcasing their potential in intelligent, multifunctional, and energy-efficient transport systems.