Silicon carbon composite material for lithium ion battery and preparation method thereof

A technology of silicon-carbon composite materials and lithium-ion batteries, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of large layer spacing, complex and cumbersome preparation process, and difficulty in industrial production, and achieve mild reaction conditions and easy preparation The process is simple and the effect of improving cycle stability

Active Publication Date: 2018-07-27
TIANNENG SAFT ENERGY JOINT CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The porous silicon structure effectively buffers the volume expansion of the lithium-ion battery during charging and discharging, and provides a fast channel for the migration of lithium ions in the lithium-ion battery. The amorphous carbon formed after the cracking of acrylonitrile in the coating layer has the characteristics of large interlayer spacing. , can increase the transmission rate of lithium-ion batteries, but the preparation process of this method is too complicated and cumbersome, and it involves processes such as pickling, deposition, and corrosion solutions, which is not easy for industrial production

Method used

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  • Silicon carbon composite material for lithium ion battery and preparation method thereof
  • Silicon carbon composite material for lithium ion battery and preparation method thereof

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] 1. Calculated according to the mass ratio, that is, the ratio of single-wall carbon tube: surfactant: solvent is 1:2:1000, disperse 0.02g single-wall carbon tube and 0.04g CMC into 20ml water, mix and stir for 2 hours, then add 0.15 g of silicon oxide powder and 2.85 g of graphite powder were transferred to a ball mill jar, rotated at high speed for 3 hours, and then dried to obtain a precursor.

[0029] The obtained precursor was heated to 600 °C at a rate of 2 °C / min in an argon atmosphere and kept at a constant temperature for 4 hours, and then naturally cooled to room temperature to obtain a single-walled carbon tube composite silicon-carbon material SWCNT / SiC.

[0030] 2. Performance analysis

[0031] Such as figure 1 As shown, the lithium-ion battery negative electrode composite material SWCNT / SiC (wherein the proportion of silicon oxide is 5%) obtained in Example 1, that is, the single-walled carbon tube composite silicon-carbon negative electrode material has v...

Embodiment 2

[0034] Calculated by mass ratio, that is, the ratio of single-walled carbon tubes:surfactant:solvent is 1:1.5:1500, disperse 0.02g single-walled carbon tubes and 0.03g PVP into 30ml ethanol, mix and stir for 3 hours, then add 0.25g The silicon oxide powder and 4.75g graphite powder were transferred to a ball mill jar, rotated at a high speed for 4 hours, and then dried to obtain a precursor.

[0035] The obtained precursor was heated up to 500°C at a rate of 4°C / min in an argon atmosphere and kept at a constant temperature for 5 hours, and then naturally cooled to room temperature to obtain a single-walled carbon tube composite silicon-carbon material.

Embodiment 3

[0037] Calculated by mass ratio, that is, the ratio of multi-walled carbon tubes:surfactant:solvent is 1:1:1200, disperse 0.02g of multi-walled carbon tubes and 0.02g of CMC into 24ml of water, mix and stir for 2h, add 0.3g of oxidation The silica powder and 2.7g graphite powder were transferred to a ball mill jar, rotated at a high speed for 4 hours, and then dried to obtain a precursor.

[0038] The obtained precursor was heated to 550°C at a rate of 3°C / min in a helium atmosphere and kept at a constant temperature for 6 hours, and then naturally cooled to room temperature to obtain a multi-walled carbon tube composite silicon-carbon material.

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Abstract

The invention discloses a silicon carbon composite material for a lithium ion battery and a preparation method thereof, belonging to the field of positive electrode materials of lithium ion batteries.The preparation method comprises the following steps: (1) adding carbon nanotubes and a surfactant into a solvent, and carrying out mixing and stirring to obtain dispersion liquid; (2) adding siliconmonooxide and graphite powder into the dispersion liquid, and successively carrying out uniform mixing and drying to obtain a silicon carbon composite precursor; and (3) calcining the silicon carboncomposite precursor in a non-oxygen atmosphere and then carrying out cooling to room temperature to obtain the silicon carbon composite material for the lithium ion battery. According to the invention, the characteristic of a high length-to-diameter ratio of the carbon nanotubes are utilized, and the carbon nanotubes are enwound with an active material to form a conductive network in the compositematerial, so the problem of the destruction of a conductive channel caused by shrinkage and expansion during the process of lithium intercalation and deintercalation are overcome; in addition, the silicon carbon composite material provided by the invention alleviates the volume expansion of silicon carbon to a certain extent, thereby improving the capacity retention rate and the cycle stability of the battery.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery electrode materials, in particular to a silicon-carbon composite material for lithium-ion batteries and a preparation method thereof. Background technique [0002] In recent years, lithium-ion batteries have attracted widespread attention from all walks of life due to their advantages such as high specific energy, long cycle life, small self-discharge, safety and reliability, and environmental protection. As the country's requirements for high specific energy batteries are getting higher and higher, silicon carbon anodes are considered to be the best choice for high specific energy battery anode materials due to their advantages such as extremely high theoretical specific capacity and low lithium intercalation potential. However, the cycle performance of silicon carbon negative electrode is not ideal. The attenuation of capacity is mainly due to the volume expansion of silicon carbon i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/62H01M10/0525
CPCH01M4/362H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 赵飞史凌俊向德波孙伟
Owner TIANNENG SAFT ENERGY JOINT CO
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