Eutectic‐Based Polymer Electrolyte With High Ionic Conductivity by Regulating Solvation for Solid‐State Lithium Metal Batteries

ABSTRACT Polymer electrolytes are promising for high‐energy‐density lithium metal batteries (LMBs), yet their widespread use is hindered by low room‐temperature ionic conductivity, narrow electrochemical stability, and poor interfacial compatibility. A novel eutectic polymer electrolyte (I‐EPE0.15) has been developed by incorporating a succinonitrile‐based eutectic electrolyte into a poly(diacetone acrylamide) matrix. Such structure enhances continuous ion transport pathways by amplifying the eutectic network and decreases the likelihood of Li + capture by the polymer's polar groups through a coordination competition mechanism. As‐prepared I‐EPE0.15 exhibits an ionic conductivity of 2.3 mS cm −1 at 30°C and a 5.1 V electrochemical stability window. The corresponding Li/Li symmetric batteries achieve stable cycling over 1000 h at 0.1 mA cm −2 , and Li/NCM811 batteries retain 70.8% of their capacity after 500 cycles at 1 C. Moreover, pouch batteries further demonstrate robust cycling and safety. This work provides a viable strategy toward stable polymer electrolytes for practical LMBs.