In situ copolymerizated gel polymer electrolyte with cross-linked network for sodium-ion batteries

High thermal stability, nonflammability, and no liquid leakage are indispensable capabilities for electrolytes in sodium-ion batteries toward large-scale energy storage systems. The use of solid-state or gel polymer electrolytes has proven to be one of the enabling tools to bring about these advancements; however, their application suffer from tedious synthesis procedure and/or lowionic transport to ensure a battery operation. Herein, a novel gel polymer electrolyte with a cross-linked polyether network (GPE-CPN) was crafted through a self-catalyzed strategy, where in situ copolymerization of two monomers, 1,3-dioxolane and trimethylolpropane triglycidyl ether is realized successfully, with the use of sodium hexafluorophosphate (NaPF6) as an initiator, at room temperature. We demonstrate that the resultant GPE-CPN possesses a superior electrochemical stability window up to 4 V versus Na+/Na, a considerable ionic conductivity, of 8.2 x 10-4S cm-1 at room temperature, which is a capability good enough to suppress the growth of sodium dendrites and thus, stabilize the interface of electrolyte/ sodium anode. Considering the benefit from its facile fabrication and superior characteristics, the asgenerated GPE-CPN reveals a potential application for future rechargeable sodium batteries.