Modified method of natural graphite material for lithium ion battery

Abstract

Disclosed is a modification method for native graphite materials used for lithium ion batteries. The method comprises the following steps that native graphite powders are placed into an autoclave, dense oxidizing acid, oxidizing salt and hydrochloric acid are used for oxidation treatment, wherein the oxidation treatment proceeds at a temperature ranging from 180 to 250 DEC G, the native graphite materials which are washed or not are centrifugalized, then native graphite materials which are centrifugalized are calcined, semi-modified native graphite materials are gained, silanization film forming treatment is completed on the semi-modified native graphite materials, then tetrahydrofuran is used to wash and dry the native graphite materials, thereby obtaining modified native graphite materials. The modified native graphite materials are capable of satisfying the application of the lithium ion batteries, have the advantages of high cost performance, low costs, large specific capacity, perfect circulative property and higher initial charge and discharge efficiency, and simultaneously are adapted to the negative pole application of high-current charge and discharge lithium ion batteries.

Description

technical field [0001] The invention relates to a preparation method of a natural graphite material for a lithium ion battery, in particular to a modification method of a natural graphite material for a lithium ion battery. Background technique [0002] Lithium-ion battery is a new type of high-energy secondary battery that began to be put into practical use in the 1990s. It has outstanding advantages such as high voltage, high energy density, good cycle performance, small self-discharge, and no memory effect. It has been widely used in mobile phones and notebooks. Computers, digital products, electric tools and other portable electronic equipment. Lithium-ion batteries have broad application prospects as the power source of electric vehicles and hybrid vehicles, as well as in military equipment, aerospace and many other fields. [0003] One of the most crucial materials in lithium-ion batteries is the anode material. The currently researched negative electrode materials i...

AI Technical Summary

Problems solved by technology

The technical problems to be solved are: 1. It is beneficial for the intercalation agent to properly increase the interlayer spacing of natural graphite and carry out deep repair between graphite layers to solve the large current of graphite materials at higher temperatures. Charge and discharge problems and improve the degree of "repair" of graphite; 2. Remove some organic and inorganic groups that affect the performance of natural graphite negative electrodes remaining on the surface of natural graphite after acid or salt treatment, so that the material can be used in future electrochemical cycles The SEI film formed in the process is dense and firm, which makes the cycle performance stable; 3. The silane coupling agent is used to react with the water and hydroxyl adsorbed by natural graphite to form And penetrating silane film, improve the firmness and stability of the SEI film formed during charge and discharge