Carbon-silicon composite negative electrode material of lithium ion battery and preparation method thereof

Abstract

The invention discloses a carbon-silicon composite negative electrode material of a lithium ion battery and a preparation method of the carbon-silicon composite negative electrode material. The negative electrode material is prepared by coating the surface of a single silicon particle with a uniform carbon-cladding layer, an impurity-element-doped carbon-cladding layer or a porous carbon-cladding layer. By adopting a hydrothermal method and subsequent calcining method, environmental friendliness can be achieved, the procedure is simple and easiness in operation can be realized; the silicon and a resilient carbon carrier form a composite material, the electrochemical performance of the silicon material can be improved through the complementary advantages under the synergistic effect of carbon and silicon components, and the primary charging-discharging efficiency and the cycling stability can be improved. The prepared silicon-carbon composite negative electrode material of the lithium ion battery has the advantages of high specific capacity, good cycling stability, safety, no pollution and the like, and an effective way is provided for the research of a high-capacity lithium ion battery.

Description

Technical field: [0001] The invention relates to the field of lithium-ion batteries, in particular to a carbon-silicon composite negative electrode material for lithium-ion batteries and a preparation method thereof. Background technique: [0002] With the depletion of fossil energy and the deterioration of the earth's climate, the development of new clean energy and the strengthening of energy conservation and emission reduction have become the key development directions of countries all over the world. In recent years, with the accelerated construction of hybrid vehicles, pure electric vehicles and new energy (solar, wind power) grid-connected power station projects, high-performance power (energy storage) batteries have become one of the core technologies for vigorous development. Currently, lithium-ion batteries are due to Its advantages such as high voltage, large capacity, good cycle performance and low pollution have become the most competitive power solution. The de...

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Problems solved by technology

The single silicon particle in the carbon-silicon composite material prepared by this method has a more uniform coating carbon layer, which promotes the formation of a stable SEI film on the surface of the composite material during charge and discharge, and is conducive to solving the problem of composite materials synthesized by traditional methods. The silicon in it will be exposed in the electrolyte, and an unstable SEI film will be formed on the silicon surface, which reduces the cycle performance of the electrode material; by selecting the carbon source or / adding an appropriate pore-forming agent / soft template at the same time, In addition, heteroelement-doped carbon-silicon composite materials and porous carbon-silicon composite materials can be prepared respectively, and the synergistic effect between the components of carbon and silicon can be used to complement each other to improve the electrochemical performance of silicon materials.

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