Lithium metal negative electrode composite modification method

Abstract

The invention relates to a composite modification method for a lithium metal negative electrode and application of the material to preparation of a lithium metal battery negative electrode, and belongs to the field of lithium metal battery negative electrode materials. Metal antimony ions and alpha-lipoic acid molecules are introduced into a reaction system, and an organic / inorganic coating layer is constructed on the surface of metal lithium by virtue of reaction among the metal antimony ions, the alpha-lipoic acid molecules and the metal lithium, so that the formation of an artificial solid electrolyte interface SEI on the surface of the metal lithium is realized; the method is simple and easy to implement, the forming speed of the coating layer on the lithium metal surface can be effectively controlled, the surface coating uniformity is improved, and the high ionic conductivity of the inorganic SEI film and the flexibility of the organic SEI film are combined, so that the cycle performance and the rate performance of the lithium metal battery are effectively improved.

Description

technical field [0001] The invention belongs to the technical field of lithium batteries, and in particular relates to a method for compound modification and modification of a lithium metal negative electrode. Background technique [0002] Lithium metal anode has the highest theoretical specific capacity (3860mAh g -1 ) and lower electrochemical potential (-3.045 V relative to standard hydrogen electrodes), have gained widespread attention from developers of next-generation lithium batteries. Lithium metal anodes can broaden the options for battery cathodes, enabling the use of lithium-free, high-capacity cathode materials such as sulfur, oxygen, and high-potential fluorides in batteries. However, the practical application of metallic lithium secondary batteries, including lithium-sulfur batteries, has been hindered by poor cycle stability and safety issues. During the continuous charge-discharge process, the uneven deposition of Li metal produces uneven electric fields an...

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Problems solved by technology

For example, α-lipoic acid has strong adsorption properties on the surface of metal lithium, and combines with lithium ions to form an organic SEI layer (patent CN112740460A), but this scheme needs to first heat α-lipoic acid above the melting point temperature to make it occur. The ring-opening reaction and free radical polymerization reaction form a polymer used as a protective film, which greatly increases the energy consumption of its production, which is not conducive to low-carbon production

[0005] In addition, in this field, the modification of α-lipoic acid on the surface of metal lithium is usually achieved by adding in the electrolyte through an electrochemical process, and α-lipoic acid cannot directly react with metal lithium alone, but regarding α-lipoic acid Lipoic acid carries out the modification of organic-inorganic composite on the surface of lithium metal, and there is no report, so the inventors have carried out research and exploration on this direction, in order to form organic-inorganic composite SEI film on the surface of lithium metal negative electrode, and give full play to the high performance of inorganic SEI film. Ion conductivity and flexibility of organic SEI films for improved cycle and rate performance of lithium metal batteries

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