Hard carbon negative electrode composite material and preparation method and application thereof

A composite material and hard carbon technology, applied in the preparation/purification of carbon, negative electrodes, battery electrodes, etc., can solve problems such as difficulty in controlling the amount of lithium fluoride attached, inconsistent pre-lithiation degrees, inconsistent material properties, etc. The effect of simplifying the production process and chemical process, reducing the amount of liquid injection, and reducing consumption

Inactive Publication Date: 2021-07-30
KUNSHAN BAOTRON NEW ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

On the one hand, the patent uses a liquid-phase method to pre-lithiate the hard carbon precursor. Specifically, lithium fluoride generated in a solution of lithium acetate or lithium oxalate and ammonium fluoride is attached to the hard carbon surface to achieve lithium fluoride. Pre-lithiation, only a small part of lithium fluoride in the system is attached to the hard carbon surface by physical adsorption, which will cause great waste and pollution, and it is difficult to control the amount of lithium fluoride attached to the hard carbon surface, so The degree of pre-lithiation between batches is inconsistent, making the properties of materials inconsistent

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  • Hard carbon negative electrode composite material and preparation method and application thereof
  • Hard carbon negative electrode composite material and preparation method and application thereof

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preparation example Construction

[0046] A method for preparing a hard carbon negative electrode composite material, comprising the steps of:

[0047] Pre-oxidizing the carbon source to prepare a pre-oxidized carbon source;

[0048] mixing the pre-oxidized carbon source and a pore-forming agent, and preparing a hard carbon precursor with a porosity of 2% to 30% by heat treatment;

[0049] mixing the hard carbon precursor with a lithium-containing compound solution, and preparing a solid pre-lithiated hard carbon precursor by a solvothermal method;

[0050] Carrying out carbon coating treatment on the pre-lithiated hard carbon precursor to form a carbon coating layer on the surface of the pre-lithiated hard carbon precursor.

[0051] Specifically, the preparation method of the hard carbon negative electrode composite material provided by the present invention includes the following steps:

[0052] S100: Pre-oxidize the carbon source to prepare a pre-oxidized carbon source

[0053] In order to avoid the relat...

Embodiment 1

[0086] This embodiment provides a hard carbon negative electrode composite material and a preparation method thereof. Specific steps are as follows:

[0087] (1) Grinding and pulverizing 1000 g of sucrose into a powder with a particle size of D50 = 80 μm, and keeping it warm at 200° C. for 10 h in an air atmosphere to obtain a pre-oxidized carbon source.

[0088] (2) 100g of pre-oxidized carbon source and 5g of potassium hydroxide are ball milled and heat-treated in a nitrogen atmosphere at a temperature of 700°C for 3 hours to prepare a hard carbon precursor with a porosity of 24%;

[0089] (3) Using a ball mill to pulverize the hard carbon precursor obtained in step (2) to obtain a hard carbon precursor with D50=15 μm, cleaning and drying;

[0090] (4) Add 10.0g of the hard carbon precursor dried in step (3) and 50g of a 10wt% lithium carbonate aqueous solution to the hydrothermal kettle, heat at 180°C for 10h, separate the solid from the liquid and dry to obtain a surface-...

Embodiment 2

[0093] This example provides a hard carbon negative electrode composite material and its preparation method. The difference from Example 1 is that the heat-treated carbon source in step (1) is replaced by sucrose with crushed coconut shell with D50=100 μm. The particle size of the finished hard carbon negative electrode composite material finally obtained is D50=5 μm, the thickness of the carbon coating layer is 50 nm, and the weight ratio of the carbon coating layer is 2.1%.

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Abstract

The invention relates to a hard carbon negative electrode composite material and a preparation method and application thereof, and the preparation method comprises the following steps: carrying out pre-oxidation treatment on a carbon source to prepare a pre-oxidized carbon source; mixing the pre-oxidized carbon source with a pore-forming agent, and preparing a hard carbon precursor with a pore structure through heat treatment; mixing the hard carbon precursor with a lithium-containing compound solution, and preparing a solid pre-lithiated hard carbon precursor by a solvothermal method; and performing carbon coating treatment on the pre-lithiated hard carbon precursor to form a carbon coating layer on the surface of the pre-lithiated hard carbon precursor. The pore-forming is beneficial to firm adhesion of a lithium-containing compound in the hard carbon or on the surface of the hard carbon in the pre-lithiation process; the hard carbon precursor is pre-lithiated by adopting a liquid phase-solvothermal method, so that the adhesive force can be enhanced, and the first-effect improvement amplitude of the pre-lithiated hard carbon can be accurately controlled by accurately controlling the addition amount of a lithium source; and the carbon coating layer can cover the lithium-carbon compound with high chemical activity, reduces the defects on the hard carbon surface, and synergistically improves the first coulombic efficiency and prolongs the cycle life of the battery.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a hard carbon negative electrode composite material and a preparation method and application thereof. Background technique [0002] Due to the frequent mileage anxiety in the experience of using electric vehicles in the current consumer market, the research and development of power batteries is increasingly developing in the direction of fast charging. The current fast-charging batteries mainly use graphite as the negative electrode. The fast-charging effect is achieved by reducing the surface density and compaction density, but it will also reduce the energy density of the battery, and the pure use of graphite as the negative electrode also has its rate limit. It is an unacceptable result for the electric vehicle consumer market. If the current negative electrode material is changed from simply using graphite to using a hard carbon material or a composite material composed ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B32/05C01D15/08H01M4/36H01M4/587H01M4/62H01M10/052H01M10/0525
CPCC01B32/05C01D15/08H01M4/366H01M4/587H01M4/628H01M4/625H01M10/052H01M10/0525H01M2004/021H01M2004/027C01P2004/82C01P2004/61C01P2004/62C01P2004/64C01P2006/40Y02E60/10
Inventor 邱昭政李冰梁世硕李文龙赵育松张永庆
Owner KUNSHAN BAOTRON NEW ENERGY TECH CO LTD
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