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

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...

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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.

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