Method for preparing carbon-coated lithium titanate negative electrode material for lithium battery

A carbon-coated lithium titanate and negative electrode material technology, which is applied to battery electrodes, circuits, electrical components, etc., can solve the problems of uncontrollable molecular chain length, high equipment and environmental requirements, and different lengths, and achieve carbon chain length Uniform and controllable, uniform carbon chain length distribution, and small molecular weight distribution

Active Publication Date: 2014-04-16
中国东方电气集团有限公司
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Problems solved by technology

[0008] The modification methods for lithium titanate materials in the above two patents all use the addition of polymers to improve the conductivity of lithium titanate, but the polymers obtained by the method are single, and the molecular chain lengths are uncontrollable and vary in length. The conductive substance used for modification in the obtained modified lithium titanate material cannot stably exert the effect of improving the conductivity
At the same time, the preparation methods of polymers used for modification in the above two patents have high requirements on equipment and environment. The polymerization method used in CN 102593444A uses a reflux device, and the reactor is relatively complicated, and a reflux tower is required; the polymerization method used in CN 102569767A The use of monomers is limited to conductive polymer monomers, and it needs to be doped with protonic acid, and the oxidant is slowly added dropwise. The process is complicated and it is difficult to industrialize continuous production.

Method used

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  • Method for preparing carbon-coated lithium titanate negative electrode material for lithium battery

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Embodiment 1

[0033] A method for preparing a carbon-coated lithium titanate negative electrode material for a lithium battery, which is prepared by the following steps:

[0034] 1) Dissolve the polymer monomer methacrylic acid, azo-type initiator azobisisobutylcyanide and trithiocarbonate in tetrahydrofuran to prepare a mixed solution, and prepare a mixed solution in a nitrogen atmosphere at 70-90 o The reaction is carried out at a temperature of C for 5-10 hours, and the reaction process is carried out in a closed reaction kettle. Wherein the molar ratio of each mixture is, methacrylic acid: azobisisobutylcyanide: trithiocarbonate=100:0.5-1: 0.01-1, the volume ratio of polymer monomer and solvent is, polymer monomer : Tetrahydrofuran=1: 1-2; Polymerization rate described in this step increases with reaction temperature and accelerates; Prepared polymer molecular weight decreases with the content increase of trithiocarbonate in the reaction raw material, increases with the reaction time a...

Embodiment 2

[0040] A method for preparing a carbon-coated lithium titanate negative electrode material for a lithium battery, which is prepared by the following steps:

[0041] 1) The polymer monomer methacrylic acid, the azo initiator azobisisoheptanonitrile and trithiocarbonate were dissolved in tetrahydrofuran to prepare a mixed solution, and the mixed solution was prepared in a nitrogen atmosphere at 80 o C temperature was reacted for 5 hours, and the reaction process was carried out in a closed reactor. Wherein the molar ratio of each mixture is, methacrylic acid: azobisisobutylcyanide: trithiocarbonate=100: 1: 0.5, the volume ratio of polymer monomer and solvent is, polymer monomer: THF=1 : 2;

[0042] 2) The solution obtained in step 1) was precipitated in methanol, and then filtered and dried to obtain a polymer.

[0043] 3) According to the molar ratio of lithium ions to titanium ions Li + : Ti + =0.8:1 Weigh lithium-containing compound lithium carbonate and titanium-containi...

Embodiment 3

[0047] A method for preparing a carbon-coated lithium titanate negative electrode material for a lithium battery, which is prepared by the following steps:

[0048] 1) The polymer monomer methyl methacrylate, the initiator azobisisobutylcyanide and trithiocarbonate were dissolved in tetrahydrofuran to prepare a solution, and the solution was prepared in a nitrogen atmosphere for 70 o C temperature for 10 hours. Wherein the molar ratio is, methyl methacrylate: azobisisobutylcyanide: trithiocarbonate=100: 0.5: 0.1, methyl methacrylate: tetrahydrofuran=1: 1.5;

[0049] 2) Precipitate the solution obtained in step 1) in methanol, then filter and dry to obtain the polymer;

[0050] 3) According to the molar ratio of lithium ions to titanium ions Li + : Ti + =0.8:1 Weigh lithium-containing compound lithium hydroxide and titanium-containing oxide rutile titanium dioxide, and weigh the polymer obtained (step 2) according to 10% of the total weight of lithium-containing compound and...

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Abstract

The invention discloses a method for preparing a carbon-coated lithium titanate negative electrode material for a lithium battery. The method comprises the following steps: preparing a polymer with controllable molecular weight by adopting living polymerization, performing ball milling and mixing with raw materials of lithium titanate, and sintering to obtain a lithium titanate material coated with a conductive carbon layer. The adopted polymerization method has the advantages that range of optional monomers is wide, polymers of different carbon chain lengths can be obtained by adjusting the raw material ratio, the carbon chain length distribution is uniform, and the finally obtained carbon-coated lithium titanate material is uniform and stable in performance. Moreover, the initial charge specific capacity of the obtained lithium titanate material reaches over 160mAh / g under the rate of 1C (1C=175mA / g), and the capacity is kept over 90 percent due to cycle of 800 times.

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 negative electrode material for a lithium battery. Background technique [0002] Lithium-ion battery is a new type of rechargeable battery. It has high volume specific energy and mass specific energy, is rechargeable and non-polluting. It is called "the most promising chemical power source" and is developing very rapidly. Lithium-ion batteries have been widely used as power sources for portable electronic products such as mobile phones, laptop computers and cameras, and are gradually used as power batteries and energy storage power sources in hybrid vehicles, pure electric vehicles and renewable energy power stations. The currently commercialized lithium-ion battery anode materials are mainly graphitized carbon materials, but there is a problem of poor safety. [0003] Spinel...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/485H01M4/62
CPCY02E60/122H01M4/485H01M4/625Y02E60/10
Inventor 李明科梁孜郑威王睿
Owner 中国东方电气集团有限公司
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