Lithium cobalt oxide composite material coated with lithium orthosilicate and carbon, preparation method and application

A technology of composite materials and lithium orthosilicate, which is applied in the preparation/purification of carbon, chemical instruments and methods, silicates, etc., can solve problems such as poor cycle stability, prevent side reactions, good electronic conductivity, and improve The effect of electrochemical performance

Pending Publication Date: 2021-08-24
SHENZHEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a lithium cobalt oxide composite material coated with lithium orthosilicate and carbon and its preparation method and application, which are used to solve the problem of existing lithium cobalt oxide materials at high The problem of poor cycle stability under voltage

Method used

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  • Lithium cobalt oxide composite material coated with lithium orthosilicate and carbon, preparation method and application
  • Lithium cobalt oxide composite material coated with lithium orthosilicate and carbon, preparation method and application
  • Lithium cobalt oxide composite material coated with lithium orthosilicate and carbon, preparation method and application

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] S5, mixed precursor: 4.8g tricobalt tetroxide and 2.3g lithium carbonate were evenly mixed, and ground for 2 hours to obtain a uniformly mixed precursor;

[0049] S6. Sintering reaction: heat-treat the homogeneously mixed precursor of S5 at 1050°C in an air atmosphere for 10 hours, the heating and cooling rates are both 5°C / min, and after cooling to room temperature, grind and sieve to obtain a powdery material;

[0050] S7, preparation of coating layer precursor: preparation of coating layer precursor: dissolve 0.3g liquid acrylonitrile low polymer in 100mL deionized water, stir evenly, then add 0.0425g tetraethyl silicate and 0.034g Lithium hydroxide monohydrate and ultrasound to obtain a mixed solution; take 2 g of the powder obtained in S6 and add it to the above solution; first stir at room temperature for 10 h, then heat and stir at 60 ° C until the solvent is evaporated to dryness, and obtain carbon source, silicon source, Lithium cobalt oxide powder evenly coate...

Embodiment 2

[0061] S9, mixed precursor: 4.8g tricobalt tetroxide and 2.3g lithium carbonate were evenly mixed, and ground for 2 hours to obtain a uniformly mixed precursor;

[0062] S10, sintering reaction: heat-treat the homogeneously mixed precursor of S9 in an air atmosphere at 1050°C for 10 hours, the heating and cooling rates are both 5°C / min, and grind to obtain a powdery material;

[0063] S11, preparation of coating layer precursor: preparation of coating layer precursor: dissolve 0.3g liquid acrylonitrile low polymer in 100mL deionized water, stir well, then add 0.085g tetraethyl silicate and 0.068g Lithium hydroxide monohydrate and ultrasound to obtain a mixed solution; take 2 g of the powder obtained in S10 and add it to the above solution; first stir at room temperature for 10 hours, and then stir at 60 ° C until the solvent is evaporated to dryness to obtain carbon source, silicon source, lithium Source uniformly coated lithium cobalt oxide powder;

[0064] S12. Secondary si...

Embodiment 3

[0066] S13, mixed precursor: uniformly mixed 4.8g of tricobalt tetroxide and 2.3g of lithium carbonate, and ground for 2 hours to obtain a uniformly mixed precursor;

[0067] S14, sintering reaction: heat-treat the homogeneously mixed precursor of S13 in an air atmosphere at 1050°C for 10 hours, the heating and cooling rates are both 5°C / min, and grind to obtain a powdery material;

[0068] S15, preparation of coating layer precursor: preparation of coating layer precursor: dissolve 0.3g liquid acrylonitrile low polymer in 100mL deionized water, stir evenly, then add 0.1275g tetraethyl silicate and 0.102g Lithium hydroxide monohydrate and ultrasound to obtain a mixed solution; take 2 g of the powder obtained in S14 and add it to the above solution; first stir at room temperature for 10 hours, and then stir at 60°C until the solvent evaporates to dryness to obtain carbon source, silicon source, lithium Source uniformly coated lithium cobalt oxide powder;

[0069] S16. Secondar...

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Abstract

The invention discloses a lithium cobalt oxide composite material coated with lithium orthosilicate and carbon as well as a preparation method and application thereof. The lithium cobalt oxide composite material comprises a lithium cobalt oxide matrix and a coating layer coating the surface of the lithium cobalt oxide matrix; and the coating layer is made of a composite material of a carbon source and a silicon source. The surface of a lithium cobalt oxide matrix is coated with a composite material of a carbon source and a silicon source, so side reaction between lithium cobalt oxide and an electrolyte, dissolution of cobalt ions and release of oxygen under a high-voltage condition can be prevented. Meanwhile, a silicon material in the coating layer is beneficial to transmission of lithium ions, a carbon material has good electronic conductivity, silicon-oxygen bonds can be weakened by doping of carbon atoms, after oxygen atoms are replaced by the carbon atoms, redundant lithium ions are formed, charge compensation is carried out, so transportation of the lithium ions is promoted, and the electrochemical performance of the lithium cobalt oxide composite material is improved on the whole.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a lithium cobalt oxide composite material coated with lithium orthosilicate and carbon, a preparation method and an application. Background technique [0002] Lithium cobalt oxide cathode material is still the first choice for lithium-ion battery cathode material in portable electronic devices due to its excellent volumetric energy density and cycle stability. However, the current commercial lithium cobalt oxide cathode material has a capacity of only 140mAh / g in the voltage range of 4.2V, which cannot meet the needs of the new generation of electronic products for high energy density batteries. After the charge cut-off voltage is increased to 4.5V, its capacity can be increased to 185mAh / g, but the cycle stability of lithium cobalt oxide is significantly reduced at high voltage. [0003] At present, the main methods for improving the performance of lithium cobaltate c...

Claims

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Application Information

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IPC IPC(8): H01M4/62H01M4/525H01M10/052C01G51/00C01B33/32C01B32/05
CPCH01M4/628H01M4/625H01M4/62H01M4/525H01M10/052C01G51/42C01B32/05C01B33/32C01P2006/40C01P2004/03C01P2004/04C01P2002/72Y02E60/10
Inventor 刘剑洪袁绮黎烈武张黔玲叶盛华
Owner SHENZHEN UNIV
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