Lithium metal protective layer and preparation method thereof and battery with protective layer

Abstract

The invention discloses a lithium metal protective layer. The preparation raw materials comprise a metal compound, a conductive agent and a binding agent, wherein the mass ratio of the metal compoundto the conductive agent to the binding agent is (6-8):1:(1-3), the metal compound is one or more of metal nitride, aluminum oxide, aluminum fluoride and Al4Li9, and the metal nitride and lithium metalcan form lithium alloy and lithium nitride through an in-situ electrochemical reaction. The lithium metal protective layer is a porous layer and provides a host material for lithium metal deposition;and in addition, the lithium metal protective layer also generates uniformly dispersed lithium alloy and / or lithium nitride in situ in the battery, so that the lithium affinity sites are enhanced, the lithium ion diffusion capacity is improved, and the generation of lithium dendrites is inhibited. The lithium metal protective layer can be prepared by slurry coating and drying, the preparation method is simple and convenient, the raw material source is cheap, and the thickness of the protective layer is easier to control. The lithium metal battery with the protective layer can inhibit the generation of lithium dendrites, and reduce the activity of lithium metal, and the cycle life of the lithium metal battery can be effectively improved.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a protective layer of electrode lithium metal, and to a preparation method thereof. Background technique [0002] Before lithium-ion batteries were introduced by Sony in Japan in 1992, lithium metal batteries had already been studied by scientists and put into practical use. But in 1989, because Li / MO 2 Lithium metal secondary batteries caught fire, and except for a few companies, most companies withdrew from the development of lithium metal secondary batteries. The research and development of lithium metal secondary batteries has basically stopped. The key reason is that during the charging process, due to the uneven surface of the lithium metal electrode, the difference in the electrodeposition rate causes uneven deposition, resulting in the generation of lithium dendrites on the negative electrode. When the lithium dendrite grows to a certain extent, it will be broken, res...

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Problems solved by technology

[0004] Nowadays, Chinese patent application CN201610252135.6 and Chinese patent application CN201610319583.3 both propose to stabilize the main body with a support structure or a skeleton structure. Although the problem of volume expansion of lithium metal deposition is solved, it cannot fundamentally reduce the density of lithium metal. active

In addition, there are also studies on the protective layer of lithium metal electrodes, which basically form a protective layer on the surface of metal lithium. For example, Chinese patent CN102315420B discloses a metal negative electrode structure with a protective layer. The organic protective film formed on the metal negative electrode and the organic protective film is formed with an inorganic layer containing metal nitride. The metal nitride is formed by the metal negative electrode contacting the flowing nitrogen, and then contacting the pyrrole compound to react to form an organic protective film. The preparation process Complicated and poor controllability; Chinese patent application CN104716381A discloses a protection method for the negative electrode of lithium-sulfur batteries, which also covers the negative electrode with a protective layer to protect lithium metal from reacting with polysulfides released by the sulfur positive electrode due to the shuttle effect , but it cannot fundamentally inhibit the activity of lithium, and inhibit the side reactions between lithium and other solvents in the electrolyte

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