A Cross-Linked Gel Polymer Electrolyte Composed of PEGDA and Acrylonitrile for High-Voltage Lithium Metal Batteries

Poly(ethylene glycol) diacrylate (PEGDA)-based gel polymer electrolytes (GPEs) offer several advantages for high-voltage lithium metal batteries (LMBs). However, the limited Li⁺ transport capability hinders the wide application of PEGDA. A cross-linked GPE consisting of PEGDA and acrylonitrile (AN) (designated as PA11 electrolyte) is synthesized through molecular design to investigate the impact of AN incorporation on the PEGDA-based GPE. AN exhibits good compatibility with PEGDA, and the resulting cross-linked copolymer effectively reduces the crystallinity of GPE, thereby enhancing its Li⁺ transport capability. At 25°C, the PA11 electrolyte exhibits high ionic conductivity (2.04 × 10⁻⁴ S cm⁻¹), broad electrochemical window (− 0.5 V to 5.32 V versus Li⁺/Li), and good stability towards lithium metal showing stable deposition and stripping of lithium for 1000 h. Additionally, LFP||Li cells assembled with designed PA11 electrolyte demonstrate discharge capacities of 150.4 mA h g⁻¹ at 0.05 C and 122.9 mA h g⁻¹ at 0.5 C. Moreover, the PA11 electrolyte can be applied in LMFP-based high-voltage LMBs with a capacity retention ratio of 84.9% after 20 cycles.