A carbon-supported nano-silicon particle structure and its preparation method and application

Abstract

The invention discloses a carbon-loaded silica nano-particle structure as well as a preparation method and an application thereof. The carbon-loaded silica nano-particle structure is characterized in that partial silicon atoms in the silica nano-particle form silicon-carbon chemical bonds on an interface with carbon; more than 50 percent of silica nano-particles are anchored onto an a-b base plane of the carbon through the silicon-carbon chemical bonds. The preparation method comprises following steps: mixing nano SiO2 (silicon dioxide), metal magnesium powder and carbon carriers, wherein the mixing method includes a direct mixing method or a method of loading the nano SiO2 onto the surface of the carbon carrier and then mixing the carbon carrier with magnesium powder; carrying out ball milling on the mixture through a ball mill in an inert gas atmosphere or vacuum condition so as to further uniformly mix the mixture; heating the mixture under the inert gas atmosphere to generate chemical reaction with SiO2, and reducing the SiO2 to be silicon; removing the reaction byproduct MgO (magnesium oxide), unreacted magnesium and insoluble impurities in an acid pickling manner; heating the mixture under the inert gas or vacuum condition, so that the silicon nano-particles react with the carbon on the interface, and the silica nano-particles are fixed on the surface of the carbon through the chemical bonds. The carbon-loaded silica nano-particle structure, the preparation method and the application are simple, feasible, low in cost and applicable to industrialized production.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a carbon-loaded nano-silicon particle structure and a preparation method and application thereof. Background technique [0002] Due to the advantages of high energy density, high operating voltage, long cycle life, low self-discharge rate, wide operating temperature range, no memory effect and no environmental pollution, lithium-ion batteries have become the preferred power source for various portable electronic devices and power tools , Large-scale application in mobile phones, digital cameras, notebook computers and other emerging industrial technology fields. In recent years, the rapid development of hybrid electric vehicles and all-electric vehicles has put forward higher and higher requirements on the energy density and other performances of lithium-ion batteries. In the structure of lithium-ion batteries, electrode materials are an important facto...

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Problems solved by technology

[0029] To sum up, in view of the problem that the volume expansion of the silicon negative electrode material during the charging and discharging process leads to the rapid decline in the capacity of the electrode, researchers have done a lot of research and achieved certain results, but for silicon / carbon Composite electrode materials, the current research still lacks in-depth and detailed research and understanding of the interface between nano-silicon and carbon matrix, and it is impossible to stabilize nano-silicon on the hydrophobic base of graphite. The cycle stability and life of the base negative electrode material are very important, and the current research uses many steps and high cost

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