Fluorine-Doped SO2 Inorganic Electrolyte for Stable Lithium Anodes

The patent changes the chemical composition parameters of the electrolyte by introducing fluorinated carbonates (FEC, DF) with specific fluorine content (0.1-5 wt%) into the carbonate electrolyte system. This parameter modification reduces the flammability of the electrolyte while maintaining its electrochemical performance, directly resolving the contradiction between performance and safety.

The patent creates a composite electrolyte system by combining traditional carbonate solvents (EC, DEC, DMC) with fluorinated additives (FEC, DF). This composite approach integrates the beneficial properties of both components: the good electrochemical performance of carbonates and the flame-retardant properties of fluorinated compounds, thereby resolving the safety-performance contradiction.

The patent introduces fluorinated carbonates as intermediary substances that mediate between the inorganic electrolyte and lithium metal. These intermediaries form protective film layers on the lithium metal surface, preventing direct harmful reactions while allowing ionic conductivity to pass through, thus resolving the contradiction between flame retardancy and lifespan.

The patent creates localized protective film layers with specific fluorine-containing compounds on the lithium metal surface. This local modification provides different properties at different locations: the film layer provides protection against reaction and dendrite formation, while the bulk electrolyte maintains high ionic conductivity and flame retardancy.