Crosslinked solubilizer enables nitrate-enriched carbonate polymer electrolytes for stable, high-voltage lithium...

High-voltage lithium metal batteries (LMBs) have been considered promising next-generation high-energy-density batteries. However, commercial carbonate electrolytes can scarcely be employed in LMBs owing to their poor compatibility with metallic lithium. N,N-dimethylacrylamide (DMAA)-a crosslinkable solubilizer with a high Gutmann donor number-is employed to facilitate the dissolution of insoluble lithium nitrate (LiNO₃) in carbonate-based electrolytes and to form gel polymer electrolytes (GPEs) through in situ polymerization. The Li⁺ solvation structure of the GPEs is regulated using LiNO₃ and DMAA, which suppresses the decomposition of LiPF₆ and facilitates the formation of an inorganic-rich solid electrolyte interface. Consequently, the Coulombic efficiency (CE) of the Li||Cu cell assembled with a GPE increases to 98.5% at room temperature, and the high-voltage Li||NCM622 cell achieves a capacity retention of 80.1% with a high CE of 99.5% after 400 cycles. The bifunctional polymer electrolytes are anticipated to pave the way for next-generation high-voltage LMBs.