Monomer Molecule Reconstruction Engineered Heterogeneous Lithium-Ion Solvation for High-Performance Lithium-Metal...

High-energy-density lithium-metal batteries (LMBs) are promising for next-generation energy storage, but their practical application is hindered by lithium dendrite growth and electrolyte interfacial instability under high-voltage conditions. Here, we report a molecule-reconstruction strategy to regulate Li⁺ solvation by exploiting the amplified steric hindrance generated during in situ polymerization of isobutyl methacrylate (IBMA). Covalently linking IBMA monomers into macromolecular chains increases steric bulk around polar ester groups, reduces the electron cloud density of carbonyl oxygen, weakens Li⁺-polymer coordination, and drives a transition from solvent-dominated to anion-rich solvation even at low salt concentrations. With TTE serving as a "molecular lubricant", the gel solid-state DEE-PIBMA electrolyte achieves a room-temperature ionic conductivity of 1.77 mS cm^-1 and practical high-voltage stability to ∼4.7 V, as confirmed by floating tests. Gel solid-state Li||NCM811 cells retain 81.8% of their initial capacity after 500 cycles at 0.5 C, while pouch cells operate stably with an energy density of 386.1 Wh kg^-1. These results highlight macromolecular backbone engineering as a general design principle for regulating solvation structures and interfacial chemistry in high-energy LMBs.