Atomic and Molecular Structure Regulated In Situ Cross-Linked Polyurethane Gel Electrolyte for High-Performance...

The incompatibility of conventional electrolytes with high-voltage cathodes and lithium metal anodes limits the performance of lithium metal batteries (LMBs). Here, an in situ cross-linked polyurethane gel electrolyte (G-P3 AR) is designed through atomic and molecular structure regulation. The polyester segments widen the highest occupied molecular orbital-lowest unoccupied molecular orbital gap, extending the electrochemical stability window to 4.97 V for compatibility with NCM811 cathodes. Polyether segments exhibit a lower Li⁺ binding energy, reducing the desolvation barrier and enhancing anode stability. At the atomic level, sp²-hybridized boron in the chain extender immobilizes anions (TFSI^- and DFOB^-) through Lewis acid-base interactions, raising the Li⁺ transference number to 0.78 and enabling exceptional rate capability (157.7 mAh g^-1 at 2 C in the Li||NCM811 cell). Hydrogen bonding between the polymer and solvent restructures the solvation sheath, promoting inorganic-rich interphases. The Li|G-P3 AR|NCM811 cell retains 81.7% capacity after 500 cycles at 0.5 C charge/1 C discharge, demonstrating a rational electrolyte design strategy for high-performance LMBs.