▎ 摘　　要

NOVELTY - The high-efficiency flame-retardant electrolyte is a non-aqueous solution with flame-retardant properties as the electrolyte, including a solvent, a solute lithium salt and optional additives. The solvent is phosphoric acid esters, halogen-containing derivatives of phosphoric acid esters, phosphazene or halogen-containing derivatives of phosphazene, which have flame retardant properties. The solute lithium salt includes a co-salt system composed of lithium tetrafluoroborate, lithium bis-oxalate borate, and lithium difluorooxalate borate and lithium nitrate. USE - High-efficiency flame-retardant electrolyte for rechargeable lithium metal battery (claimed) used in fields such as portable electronic devices and electric vehicles. ADVANTAGE - The high-efficiency flame-retardant electrolyte has excellent compatibility to lithium metal cathode and anode material, thus ensuring excellent battery electrochemical performance and greatly improving the safety of the lithium metal battery. The method is easy to adjust the type and proportion of the solvent and the solute, and has simple and flexible operation, strong controllability and good consistency. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a preparation method of the high-efficiency flame-retardant electrolyte for lithium metal battery, which involves dissolving one or more of lithium tetrafluoroborate, lithium bis-oxalate borate and lithium difluorooxalate borate in a solvent composed of a phosphorus-containing organic compound, adding additive 1 and lithium nitrate or additive 2 in which lithium nitrate is dissolved, and stirring for 24-48 hours, so that the electrolyte is stirred uniformly; and (2) a rechargeable lithium metal battery with high safety flame retardant and long cycle life, which comprises batteries that are layered, spinel transition metal oxides capable of reversibly deintercalating lithium ions, or organic compounds containing electrochemically active functional groups, the compound is used as the positive electrode active material, the metal current collector is used as the positive electrode carrier, the positive electrode is prepared by adding binder and conductive agent, and the lithium-based material is used as the negative electrode active material. DESCRIPTION OF DRAWING(S) - The drawing shows a cycling performance of lithium metal batteries of electrolyte with NCM811 positive electrode. (Drawing includes non-English language text)