Preparation method of high-safety metal composite negative electrode

Abstract

The invention relates to a preparation method of a high-safety metal composite negative electrode. The preparation method comprises the following steps: (a) heating metal lithium to a fused state under the protection of inert gas; (b) adding an inorganic non-metal compound into the metal lithium with the fused state; after stirring and reacting, cooling, wherein the inorganic non-metal compound isselected from one or a mixture of more of sulfide, phosphide, nitride and fluoride, and the mass ratio of the metal lithium to the inorganic non-metal compound is (10 to 3) to 1. According to the preparation method, a compound protection layer can be formed on a lithium negative electrode so that electrolyte and a lithium sheet are effectively isolated and the lithium sheet is prevented from corrosion and reaction; uniform distribution of lithium ions is realized and lithium dendrites are prevented from being generated; a framework supporting effect is provided.

Description

technical field [0001] The invention belongs to the field of lithium batteries, and relates to a method for preparing a metal negative electrode, in particular to a method for preparing a high-safety metal composite negative electrode. Background technique [0002] The energy density of metal lithium anode is 3860mA h / g, which is more than 10 times higher than the theoretical capacity of traditional graphite anode, which is expected to greatly improve the standby time of portable electronic products and the cruising range of electric vehicles. hotspots in industry research. Batteries that use metal lithium as the negative electrode mainly include solid-state lithium batteries (gel, ceramic or their mixtures as electrolytes), lithium-sulfur batteries, lithium-oxygen batteries, and lithium-intercalated compound lithium batteries (such as lithium iron phosphate, lithium nickelate, cobalt acid, etc.) Lithium, lithium manganese oxide, ternary cathode materials, lithium-rich batt...

AI Technical Summary

Problems solved by technology

However, in the process of practical application of these batteries, batteries using metal lithium as the negative electrode face a series of problems: such as the poor stability and safety caused by the formation of dendrites during cycling; in addition, lithium dendrites are broken. Becoming dead lithium leads to poor cycle life and capacity reduction of the entire battery, and even a series of safety issues such as short circuit, thermal runaway, fire and explosion due to dendrites breaking through the diaphragm

However, the SEI film produced by this coating method is uneven and uneven, and it is easy to fall off, which makes the electric field distribution on the surface of lithium metal uneven, which cannot effectively eliminate the side reaction between lithium metal and electrolyte, and is not suitable for lithium metal. Long-term cycle use of secondary batteries, resulting in uneven deposition of lithium and formation of lithium dendrites

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