Long-cycling and safe lithium metal batteries enabled by the synergetic strategy of ex situ anodic pretreatment and an in-built gel polymer electrolyte

The wide application of lithium metal batteries (LMBs) is greatly limited by the notorious side reactions and dendrite growth due to the highly reactive nature of lithium metal paired with the traditional liquid electrolytes. Herein, we report a synergetic strategy by combining ex situ chemical pretreatment on lithium metal anodes (LMAs) and in situ cationic polymerization of DOL to tackle these issues. LiDFOB is unprecedentedly employed as the initiator to launch the in situ fabrication of poly-DOL gel polymer electrolytes (GPEs), resulting in integrated ionic connections between the electrodes and electrolyte. Furthermore, robust and compatible interfaces are successfully constructed via pretreatment of LMAs and establishment of a LiDFOB-LiTFSI dual-salt system in quasi-solid lithium metal batteries (QSLMBs). Consequently, both the solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI) containing N- , F- , and B-rich inorganic components are formed on the anode and cathode. The novel poly-DOL GPE exhibits excellent compatibility with various intercalating cathodes, such as LiFePO4, LiMn2O4 and LiCoO2. This work provides a facile and accessible approach to manufacture qualified LMBs with improved safety and elongated lifetime.