Preparation process of metal lithium negative electrode with surface protection layer

Abstract

The invention relates to a preparation process of a metal lithium negative electrode with a surface protection layer. The preparation process comprises the following steps: 1, dissolving a lithium salt or / and an inorganic solid electrolyte and a polymer and mixing in a polyimide solution to obtain a polyimide mixed solution; 2, coating the surface of one side of a metal lithium foil with the mixedsolution, wherein the coating thickness is 1-150 microns; and 3, drying the surface of the metal lithium foil coated with the mixed solution to form a polymer network for coating the inorganic fillerso as to form a surface protection layer on the surface of the metal lithium foil in situ. The invention aims to inhibit the growth of the metal lithium negative electrode in a battery, and through the polyimide protection layer with high mechanical strength, the metal lithium makes close contact with the protection layer by using an in-situ growth method, so that the interface impedance is reduced, and the coulombic efficiency of the battery is improved; and the ionic conductivity of the protection layer is improved by adding the lithium salt / solid electrolyte, and the rate capability is improved.

Description

technical field [0001] The invention relates to the technical field of energy storage batteries, in particular to a preparation process of a metal lithium negative electrode with a surface protection layer applied in batteries. Background technique [0002] Under the background of increasingly tense energy sources, countries all over the world are focusing on the research of green and environmentally friendly new energy sources. At the same time, people's demand for batteries for electronic products is also developing in the direction of high energy density and high safety. Lithium secondary batteries have attracted extensive attention from researchers in the industry because of their high specific energy, environmental protection and pollution-free. The secondary battery with metal lithium as the negative electrode has a high theoretical specific capacity and low electrode potential, so it has become a research direction to greatly increase the capacity of the secondary bat...

AI Technical Summary

Problems solved by technology

[0005] The existing problems are: the inorganic fillers that do not contain lithium in the surface protective layer materials currently used rely on their high mechanical strength to suppress lithium dendrites; pure ceramic solid electrolytes have high ion conductivity and high mechanical strength, but It has poor contact with the metal lithium negative electrode, and the interface resistance is high, which reduces the rate performance of the battery; the ionic conductivity of the pure polymer protective layer is low, which reduces the cycle performance of the battery, and the polymer currently used has low mechanical strength. , lithium dendrites may still pierce the protective layer