Flame-retardant electrolyte, preparation method and lithium metal battery

Abstract

The invention provides a flame-retardant electrolyte, and the electrolyte comprises a lithium salt and an organic liquid; the organic liquid comprises a first component and a second component; the first component is an ester or ether organic solvent, and the second component is a phosphazene flame retardant, wherein the lithium salt is dissolved in the first component and is not dissolved in the second component. The first component accounts for 5-90% of the mass of the organic liquid, and the second component accounts for 10-95% of the mass of the organic liquid. According to the flame-retardant electrolyte provided by the invention, the solvation structure of lithium ions can be regulated and controlled, a compact and uniform solid electrolyte interface layer is formed on the surface of an electrode, and uniform nucleation and stable deposition of lithium metal are realized. The flame-retardant electrolyte can inhibit the growth of lithium dendrites and the formation of dead lithium, and improves the coulombic efficiency and cycle stability of the lithium metal battery. Meanwhile, the electrolyte has good incombustibility, and the safety performance of the lithium metal negative electrode can be greatly improved. The invention also provides a preparation method of the flame-retardant electrolyte and a lithium metal battery.

Description

technical field [0001] The present application relates to the technical field of lithium batteries, in particular to a flame-retardant electrolyte, a preparation method and a lithium metal battery. Background technique [0002] Lithium metal has an ultra-high theoretical specific capacity (3860mAh / g) and the lowest electrode potential -3.045V (compared to the standard hydrogen electrode), which is a potential next-generation high-energy-density anode material. However, there are many problems in the lithium metal negative electrode that have not been solved, such as side reactions easily occur at the lithium-electrolyte interface, and an unstable solid-electrolyte interphase (SEI) film is formed. The SEI film is easily destroyed repeatedly during the charge and discharge process, resulting in the generation of a large number of dendrites and dead lithium, thereby reducing the Coulombic efficiency and cycle stability of the lithium metal anode. What's more deadly is that the...

AI Technical Summary

Problems solved by technology

However, there are many problems in the lithium metal negative electrode that have not been solved, such as side reactions easily occur at the lithium-electrolyte interface, forming an unstable solid-electrolyte interphase (SEI) film.

The SEI film is easily destroyed repeatedly during charge and discharge, resulting in a large number of dendrites and dead lithium, thereby reducing the Coulombic efficiency and cycle stability of the lithium metal anode.

What's more deadly is that the growth of dendrites and the accumulation of dead lithium can easily pierce the separator, causing a short circuit in the battery, causing thermal runaway and even fire

Images