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Preparation method for carbon-tin composite negative electrode material

A negative electrode material and polymer technology, applied in battery electrodes, electrical components, circuits, etc., can solve the problems of poor cycle performance and limited application of tin-based materials

Pending Publication Date: 2016-04-27
SHENZHEN BAK POWER BATTERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Graphite-based materials have good cycle performance, but their actual capacity has basically reached the theoretical capacity (372mAh / g), which limits its application in high energy density chemical power sources; tin-based materials have high specific energy (994mAh / g) , but the cycle performance of tin-based materials is poor

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  • Preparation method for carbon-tin composite negative electrode material

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preparation example Construction

[0023] The preparation method of the carbon-tin composite negative electrode material of one embodiment, comprises the following steps:

[0024] Step S1, dissolving the acrylonitrile polymer in an organic solvent to obtain an organic solution.

[0025] Further, the acrylonitrile polymer is selected from polyacrylonitrile, acrylonitrile-itaconic acid copolymer, acrylonitrile-methyl itaconate copolymer, acrylonitrile-methyl acrylate copolymer, acrylonitrile-styrene copolymer And at least one of acrylonitrile-acryl ester copolymers.

[0026] Further, the organic solvent is at least one selected from N-methylpyrrolidone, dimethylsulfoxide, ethanol and N,N-dimethylformamide.

[0027] Further, the acrylonitrile polymer and the organic solvent are stirred at 50-100° C. for 1.5-2 hours to obtain an organic solution, and the molar concentration of the acrylonitrile polymer in the organic solution is 10%-40%.

[0028] Step S2, mixing tin oxide and graphite to obtain a carbon-tin mixtu...

Embodiment 1

[0048] To prepare an organic solution, dissolve acrylonitrile-methyl acrylate copolymer in N-methylpyrrolidone to prepare 10 g of an organic solution with a molar concentration of 10%, stir and heat at 80°C for 2 hours to obtain a uniform organic solution;

[0049] Prepare a carbon-tin mixture, weigh 4g of graphite and 1g of a mixture of tin dioxide and stannous oxide with a mass ratio of 7.5:1, put it into a stainless steel ball mill jar, and weigh stainless steel balls of corresponding weight according to the ball-to-material ratio of 15:1, Using a high-energy ball mill, 1000r / min ball milling and mixing for 2 hours to obtain a carbon-tin mixture;

[0050] To prepare the precursor, take 10g of the above-prepared organic solution and 5g of the carbon-tin mixture, put them together into a polytetrafluoroethylene ball mill jar, weigh the corresponding weight of agate balls according to the ball-to-material ratio of 15:1, and add 10mL The silane coupling agent is used as a dispe...

Embodiment 2

[0054] To prepare an organic solution, dissolve acrylonitrile-styrene copolymer in dimethyl sulfoxide to prepare 10 g of an organic solution with a molar concentration of 40%, stir and heat at 50° C. for 2 hours to obtain a uniform organic solution;

[0055] Prepare a carbon-tin mixture, weigh 9g of graphite and 6g of stannous oxide, put them into a stainless steel ball mill tank, weigh stainless steel balls of corresponding weight according to the ball-to-material ratio of 15:1, and use a high-energy ball mill to mix for 2 hours at 1000r / min. Get a carbon-tin mixture;

[0056] To prepare the precursor, take 3g of the above-prepared organic solution and 15g of the carbon-tin mixture, put them together into a polytetrafluoroethylene ball mill jar, weigh the corresponding weight of agate balls according to the ball-to-material ratio of 15:1, and add 30mL of sunflower Alcohol is used as a dispersant, using a planetary ball mill with a speed of 500r / min, ball milling for 8 hours, ...

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Abstract

A preparation method for a carbon-tin composite negative electrode material is disclosed. The preparation method comprises the following steps of dissolving an acrylonitrile polymer into organic solvent to obtain an organic solution; mixing tin oxide with graphite to obtain a carbon-tin mixture; after uniformly mixing the organic solution, the carbon-tin mixture and a dispersant, removing the organic solvent and the dispersant, and drying to obtain a precursor; and performing calcining on the precursor under a protective gas to obtain the carbon-tin composite negative electrode material. Acrylonitrile is mixed with the carbon-tin mixture, so that tin can be fully dispersed into the acrylonitrile polymer component and the carbon medium of graphite, and the problem of volume expansion and agglomeration of tin in the circulating process is effectively overcome; and the acrylonitrile polymer pyrolytic carbon and graphite are both high in conductivity, so that the carbon-tin composite negative electrode material is better in cycling performance and higher in capacity retention ratio.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a preparation method of a carbon-tin composite negative electrode material. Background technique [0002] As an important chemical power source, lithium-ion batteries have many advantages such as high working voltage, high specific capacity, long cycle life, fast charging, no memory effect, and environmental protection. They are used in notebook computers, mobile phones, camcorders, weapons, etc. Equipment and other mobile electronic terminal equipment occupies a dominant position. [0003] The performance of a lithium-ion battery depends fundamentally on the performance of its positive and negative electrode materials, and the performance of the negative electrode material is an important factor. [0004] At present, the negative electrodes of commercial lithium-ion batteries mainly use graphite and tin-based materials. Graphite-based materials have good cycle performance,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/1393H01M4/1395H01M4/139
CPCY02E60/10
Inventor 廖勇来
Owner SHENZHEN BAK POWER BATTERY CO LTD