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A method for preparing carbon-coated lithium titanate

A technology of carbon-coated lithium titanate and titanium ions, which is applied to lithium batteries, structural parts, electrical components, etc., can solve problems such as the inability to prevent the agglomeration of lithium titanate, the inability to ensure uniformity and compactness, and the complexity of the precursor process. The effect of polymer coating on the surface of lithium titanate is tight, the particles of lithium titanate are uniform, and the requirements for technology and equipment are not high

Active Publication Date: 2017-02-22
中国东方电气集团有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in CN101944590A, the preparation process of the precursor by the hydrothermal method is complex and requires high temperature and high pressure, and the introduction of the carbon source is directly added and stirred, which cannot ensure uniformity and compactness.
In CN102593444A, phenolic resin is used to coat lithium titanate, and the polymer is directly mixed with lithium titanate. Although the combination of carbon source and lithium titanate is closer than that of general mechanical mixing, the polymer is randomly mixed in lithium titanate. The uniformity is not good, and the agglomeration of lithium titanate cannot be prevented

Method used

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Embodiment 1

[0030] A method for preparing carbon-coated lithium titanate, comprising the following steps:

[0031] 1) According to the molar ratio of lithium ions to titanium ions Li + : Ti + =0.82:1 The lithium-containing compound and the titanium-containing oxide were weighed, milled in a ball mill jar for 4 hours, and then sintered for 8 hours to obtain precursor A. In this step, the longer the sintering time, the required Li + : Ti + The higher the ratio; the longer the milling time and the shorter the sintering time, the smaller the particle size of the precursor.

[0032] 2) Add 200g of precursor A and 1L of distilled water obtained in step 1) into the reaction kettle, then add 60g of monomer methyl methacrylate (MMA) and 2g of emulsifier SDS, vacuumize, pass nitrogen and stir until the system is fully emulsified (The full emulsification means that there are no obvious large solid particles or liquid droplets in the system, and no obvious sedimentation) and then heated to 60°C, ...

Embodiment 2

[0036] A method for preparing carbon-coated lithium titanate, comprising the following steps:

[0037] 1) Weigh the lithium-containing compound and titanium-containing oxide according to the molar ratio of lithium ions to titanium ions Li+:Ti+=0.8:1, ball mill in a ball mill tank for 6 hours and then sinter for 5 hours to obtain precursor A.

[0038] 2) Add 800g of precursor A and 1L of distilled water obtained in step 1) into the reaction kettle, then add 160g of monomeric ethyl methacrylate and 3.5g of emulsifier, vacuumize and stir with nitrogen, and heat the system until it is fully emulsified 65°C, slowly add the initiator ammonium persulfate aqueous solution (ammonium persulfate content 0.5g) at this temperature, stop heating after 4 hours of reaction, continue stirring after the reaction is over, add methanol to break the emulsion after cooling, and then use a large amount of Precipitate with methanol, and filter to obtain composite particle precursor B (polyethyl metha...

Embodiment 3

[0041] A method for preparing carbon-coated lithium titanate, comprising the following steps:

[0042] 1) According to the molar ratio of lithium ions to titanium ions Li + : Ti + =0.84:1 The lithium-containing compound and the titanium-containing oxide were weighed, ball milled in a ball mill jar for 8 hours, and then sintered for 10 hours to obtain precursor A.

[0043] 2) Add 700g of precursor A and 1L of distilled water obtained in step 1) into the reaction kettle, then add 70g of monomeric methyl methacrylate and 3g of emulsifier, vacuumize and stir with nitrogen, and heat to 70 after the system is fully emulsified °C, slowly add the initiator ammonium persulfate aqueous solution (ammonium persulfate content 0.4g) at this temperature, stop heating after 4 hours of reaction, continue stirring after the reaction is over, add methanol to break the emulsion after cooling, and then use a large amount of methanol Precipitate and filter to obtain composite particle precursor B (...

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Abstract

The present disclosure discloses a method for preparing carbon-coated lithium titanate, and provides a method for preparing a carbon-coated lithium titanate anode material for a lithium battery. The method prepares a lithium titanate precursor first, then coats a polymer on the surface of the precursor through emulsion polymerization, and finally performs sintering, and obtaining a carbon-coated lithium titanate material. The present disclosure obtains a carbon source of the polymer through the emulsion polymerization. The carbon source is coated on the surface of lithium titanate uniformly and compactly with a better coating effect than a common mechanical mixing method. The polymer is coated while agglomeration of a lithium titanate crystal is prevented during the emulsion polymerization process, and an obtained product has a small particle size and a uniform size. The carbon-coated lithium titanate prepared by the present disclosure has excellent cycling performance during charging and discharging at a high rate.

Description

technical field [0001] The invention relates to a preparation method of a negative electrode material of a lithium ion battery, in particular to a preparation method of a carbon-coated lithium titanate material. Background technique [0002] Spinel lithium titanate (Li 4 Ti 5 o 12 ) is a relatively popular anode material for lithium-ion batteries in recent years. The material has a high lithium potential (1.55V), will not react with common electrolytes to form an SEI film, and will not cause lithium precipitation during overcharge. Lithium titanate has a unit cell volume change of less than 1% when inserting and extracting lithium ions. It is called a "zero strain" material and has a long theoretical cycle life. However, the electronic conductivity of lithium titanate is poor, and the capacity is easy to decay when charging and discharging at a high rate. Therefore, in order to improve the electronic conductivity of lithium titanate, the carbon coating method is widely u...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/485
CPCH01M4/366H01M4/485H01M4/625H01M10/0525H01M4/131H01M4/1391H01M4/583H01M4/587H01M10/052Y02E60/10
Inventor 李明科梁孜王睿
Owner 中国东方电气集团有限公司