Molecular engineering of a gel polymer electrolyte via in-situ polymerization for high performance lithium metal batteries

Solid-state lithium (Li) metal batteries have been considered as the candidate for the next generation power system for their outstanding performance in energy density and safety. Nevertheless, while solid-state electrolytes are still plagued by incompatible interphases, Li metal anode also has been hindered by dendrites growth. Herein, a facile in-situ synthesis of gel polymer electrolyte (GPE) with polyethylene glycol dimethacrylate (PEGDMA) and pentaerythritol tetraacrylate (PETEA) as the hybrid polymer skeleton, for the first time, is employed to deal with these issues. The GPE displays high ionic conductivity (7.6 mS cm−1) at room temperature and high stability towards Li metal anode. More interestingly, the in-situ GPE can construct a uniform and stable SEI on the surface of Li metal anode and guarantee a long cycling life (>500 cycles) with a capacity retention of 90% in the LiFePO4|GPE|Li battery. This GPE with hybrid polymer skeletons opens up an innovative idea for the electrolyte design that will eventually promote the practical application of lithium metal batteries.