High-performance silicon monoxide/amorphous carbon/graphite composite negative electrode material and preparation method thereof

Abstract

The invention discloses a high-performance silicon monoxide / amorphous carbon / graphite composite negative electrode material. The high-performance silicon monoxide / amorphous carbon / graphite composite negative electrode material comprises the following components in parts by weight: 5-7 parts of silicon monoxide, 1-2 parts of carbohydrate and 1-4 parts of natural flake graphite. The preparation method of the composite negative electrode material comprises the following steps of: mixing the materials; carrying out high-energy ball milling and high-temperature pyrolysis; and grinding and sieving to obtain the composite material. The composite negative electrode material is excellent in cycle performance and capacity performance, so that a certain feasibility choice is provided for practicability of the SiO negative electrode material. Moreover, the preparation method is simple to operate, environment-friendly, pollution-free and easy to popularize.

Description

technical field [0001] The invention belongs to the field of electrochemical power sources, and in particular relates to a silicon monoxide / amorphous carbon / graphite composite negative electrode material for a lithium ion battery and a preparation method thereof. Background technique [0002] Since the research and development and success of lithium-ion batteries in the early 1990s, with its superior performance (such as high operating voltage, high specific energy, good cycle performance, long service life, wide operating temperature range, no memory effect, small self-discharge, Pollution-free and other advantages) has become the battery system with the best comprehensive performance at present. However, with the miniaturization of portable electronic products and the increasing demand for lithium-ion batteries in aviation, military and automotive industries, the capacity and energy density of batteries need to be greatly improved. At present, commercial lithium-ion batte...

AI Technical Summary

Problems solved by technology

On the one hand, the SiO grain size is reduced to the submicron or nanometer level by high-energy ball milling to reduce the absolute volume change of the particles. The phenomenon of "electrochemical sintering" is prone to occur, and the cycle performance is reduced instead; on the other hand, nano-SiO particles are dispersed in the matrix of the electrochemically inert phase or the electrochemically active phase, and the volume change of the silicon particles is absorbed by the matrix phase to prevent particle pulverization fail

Among them, the most widely used method is to disperse SiO particles in an amorphous carbon matrix by hydrothermal carbonization, high-temperature pyrolysis of organic precursors (polyvinyl alcohol, polyfurfuryl alcohol, etc.), chemical vapor deposition, and sol-gel methods. x / C composite anode material can effectively improve the cycle performance of SiO anode materials by taking advantage of the advantages of amorphous carbon, such as light weight, small volume effect and good conductivity, but its long-term cycle stability and capacity performance still need to be improved.

In addition, Si / SiO with core-shell, nested and porous structures can be prepared by using high-temperature disproportionation reaction of SiO, thermal reduction of metals (Mg, Li, etc.), chemical etching, etc. x Composite negative electrode material, the prepared composite material has excellent cycle performance and high reversible capacity, but the preparation process is complicated, high preparation cost, even need to use highly corrosive and toxic HF as etching solution, so that impedes its practical application

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