Lithium negative electrode pretreatment protection agent, lithium negative electrode pretreatment protection method and lithium negative electrode with protective layer

Abstract

An embodiment of the present invention provides a lithium negative electrode pretreatment protective agent, the lithium negative electrode pretreatment protective agent includes a compound containing a sulfonyl fluoride structure represented by formula (1), wherein R is an n-valent hydrocarbon group, a substituted hydrocarbon group or Hydrocarbyloxy group, n is an integer of 1-3; the sulfur atom in the sulfonyl fluoride structure is connected with the carbon atom in the hydrocarbyl group, the substituted hydrocarbyl group or with the oxygen atom in the hydrocarbyloxy group. Using the pretreatment protective agent to pretreat the lithium negative electrode can form a protective layer rich in lithium fluoride and sulfur-containing compounds in situ on the surface of the lithium negative electrode, thereby effectively stabilizing the lithium negative electrode, reducing side reactions and alleviating lithium dendrites. produced to improve the coulombic efficiency and safety of lithium batteries. Embodiments of the present invention also provide a lithium negative electrode pretreatment protection method and a lithium negative electrode with a protective layer.

Description

technical field [0001] The embodiments of the present invention relate to the technical field of lithium secondary batteries, and in particular, to a lithium negative electrode pretreatment protection agent, a lithium negative electrode pretreatment protection method, and a lithium negative electrode with a protective layer. Background technique [0002] With the rapid development of science and technology, consumers have higher and higher energy density requirements for mobile terminal equipment, and the energy density of lithium-ion batteries based on traditional graphite anodes is close to the ceiling. The use of metal lithium negative electrodes can greatly improve the energy density of lithium batteries and significantly improve the user experience. However, the lithium metal anode has the characteristics of high chemical activity (resulting in low Coulomb efficiency), lithium dendrite growth (causing side reactions and safety hazards) and large volume expansion (the SE...

AI Technical Summary

Problems solved by technology

However, the lithium metal anode has the characteristics of high chemical activity (resulting in low Coulombic efficiency), lithium dendrite growth (causing side reactions and safety hazards), and large volume expansion (continuous rupture and reconstruction of the SEI film), which hinder high energy density metal lithium batteries. commercialization process

[0003] In view of the problems existing in the above lithium metal anodes, the current mainstream strategies are the following four aspects: 1) Electrolyte engineering regulates lithium deposition, and improves the deposition / dissolution coulombic efficiency of metal lithium by optimizing the electrolyte composition and / or adding additives, although This strategy is highly operable and effective, and it is one of the effective ways to improve the stable cycle of lithium anodes. However, the appropriate electrolyte formulation and additives are the difficulties of current research and require long-term iterative optimization; 2) Solid electrolytes inhibit dendrite spreading, The use of solid-state electrolytes can inhibit or slow down the growth of lithium dendrites to a certain extent, but it cannot fundamentally solve the problem of lithium dendrites, and the contact between solids and solids will cause serious interface problems; 3) Customize the main body to limit the volume change, using Customized hosts (such as 3D current collectors or 3D nanoskeletons) can alleviate lithium dendrites and volume changes to a large extent, but the absence of lithium sources in the customized host itself, or the decrease in specific capacity after compounding lithium metal, will directly affect its high energy efficiency. Density characteristics; 4) Interface engineering stabilizes the lithium anode, builds a stable interface on the surface of the lithium anode by physical or chemical means, realizes uniform lithium ion flow, improves Coulombic efficiency and alleviates lithium dendrite growth, although the operation method of this strategy is simple, It is highly targeted and has certain practical value, but there is no technical solution that is both effective and large-scale practical

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