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

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.