Amide Monomer‐Mediated Solubilization Strategy Enables Nonflammable Deep Eutectic Gel Polymer Electrolytes for High‐Temperature‐Stable Lithium Metal Batteries

ABSTRACT Deep eutectic gel polymer electrolytes (DEGPEs), combining intrinsic non‐flammability with outstanding thermal stability, are attractive candidates for next‐generation lithium metal batteries (LMBs). However, their practical deployment in high‐energy‐density LMBs has been fundamentally constrained by poor interfacial stability with the lithium metal anode and limited tolerance toward the high‐voltage cathode. We report a new amide‐monomer‐mediated DEGPE that achieves comprehensive performance via a LiNO 3 solubilization strategy. The N‐methylacrylamide (NME) units in the poly(N‐methylacrylamide) (PNME) framework enhance LiNO 3 solubility through hydrogen bonding and Li + coordination, forming a stable inorganic‐rich interphase. Concurrently, it immobilizes free N‐methyltrifluoroacetamide (NMTFA) via hydrogen bonds, suppressing transition‐metal dissolution and preventing electrolyte leakage. The amide monomer‐mediated DEGPE‐based NCM811||Li cells achieve 80.1% capacity retention after 500 cycles with an average Coulombic efficiency of 99.67%, a performance that surpasses state‐of‐the‐art (deep eutectic electrolyte) DEE‐based systems. More impressively, LCO||Li cells retain 89.6% capacity after 300 cycles even at an elevated temperature of 80°C, far exceeding the thermal stability limits of conventional electrolytes and underscoring its remarkable interfacial stability under extreme operational conditions. This work establishes a molecularly engineered solvation and interfacial regulation strategy for DEGPEs, providing both fundamental insight and a practical pathway toward safe, high‐energy, and high‐temperature‐tolerant LMBs.