A kind of preparation method of lithium cobalt oxide cathode material coated with fluorinated carbon black

Abstract

The invention relates to a method for preparing a fluorinated carbon black coated lithium cobalt oxide cathode material. The method comprises the following steps: (1) preparing a lithium cobalt oxide material, wherein the chemical formula of the lithium cobalt oxide material is LiCo<1-x-y>FexAlyO2, x is equal to 0.15-0.2, and y is equal to 0.2-0.3; (2) preparing fluorinated carbon black, namely performing oxidation treatment on carbon black powder with the particle size of 10-20 microns, adding the powder in a closed vacuum reactor, introducing fluorine under a nitrogen atmosphere, heating to the temperature of 200-250 DEG C, reacting for 2-3 hours, stopping heating, cooling the reactor to room temperature, replacing the residual fluorinated gas by adopting nitrogen, thereby obtaining the fluorinated carbon black, wherein the partial pressure of the fluorine is maintained to be 50-70KPa when the reaction starts; and (3) coating. According to the cathode material prepared by the method, Fe and Al are doped into lithium cobalt oxide for modifying so as to improve the activity of the material, the surface of the lithium cobalt oxide is coated with the fluorinated carbon black, and the conductivity and cycling stability of the material can be further improved. Therefore, when the composite material is used for a lithium ion battery, the battery has high first discharge reversible capacity and long service life.

Description

technical field [0001] The invention relates to a preparation method of lithium cobalt oxide cathode material coated with fluorinated carbon black. Background technique [0002] With the technological advancement and demands of mobile devices, the demand for secondary batteries as energy sources has increased dramatically. Among such secondary batteries, lithium secondary batteries having high energy density and operating potential, long life cycle, and reduced self-discharge are widely used in the related art. [0003] For positive electrode active materials for lithium secondary batteries, lithium-containing cobalt oxides (LiCoO 2 ). In addition, lithium-containing manganese oxides such as LiMnO having a layered crystal structure can also be used 2 , LiMn with spinel crystal structure 2 o 4 etc. and lithium-containing nickel oxides (LiNiO 2 ). [0004] LiCoO 2 It is the main cathode material for commercial lithium-ion batteries at present, but it has disadvantages ...

AI Technical Summary

Problems solved by technology

[0004] LiCoO 2 It is the main cathode material for commercial lithium-ion batteries at present, but it has disadvantages such as expensive, not conducive to environmental protection, and low specific capacity.

LiNiO 2 The positive electrode material doped with Co element also has LiNiO 2 The high discharge specific capacity of the material stabilizes the layered structure of the material and enhances the cycle stability of the material, but this material also has defects such as poor overcharge resistance, poor thermal stability, and high irreversible capacity for the first discharge.