High-stability silicon-carbon negative electrode material and preparation method thereof

Abstract

The invention discloses a high-stability silicon-carbon negative electrode material and a preparation method thereof. The high-stability silicon-carbon negative electrode material comprises a porous silicon core and a carbon coating shell, wherein the outer side of the porous silicon core is coated with the carbon coating shell, and an expansion gap is reserved between the porous silicon core andthe carbon coating shell. The preparation method comprises the following steps of carrying out high-temperature treatment on micron-sized SiO2 powder at 950 DEG C for 5 hours; obtaining Si / SiO2 mixture; carrying out HF acid etching treatment on the Si / SiO2 mixture; removing SiO2, further, forming a porous silicon core with a porous structure; the porous structure providing an expansion space for volume expansion formed by the porous silicon core in the charging and discharging process; and preventing the phenomenon that the silicon-carbon negative electrode material is powdered after the porous silicon core is not shrunk and expanded so that the silicon-carbon negative electrode material has higher stability, an expansion gap is formed between the porous silicon core and the carbon coatingshell, an expansion gap provides an expansion space for volume expansion formed by the porous silicon core in the discharge process, and a problem of expansion of the porous silicon core in the carbon coating shell is more effectively solved.

Description

technical field [0001] The invention relates to the technical field of battery negative electrode materials, in particular to a highly stable silicon-carbon negative electrode material and a preparation method thereof. Background technique [0002] In the existing secondary battery system, lithium-ion batteries are currently the most competitive secondary batteries in terms of development space and technical indicators such as life, specific energy, working voltage and self-discharge rate. With the continuous development of electronic technology, higher requirements are put forward for lithium-ion batteries, which require higher energy density, better cycle life, better high and low temperature charge and discharge performance and safety performance, etc., which requires lithium The cathode and anode materials for ion batteries need to be further developed and improved. [0003] Carbon materials, such as natural graphite, graphitized mesocarbon microspheres, etc., are widel...

AI Technical Summary

Problems solved by technology

However, in the existing methods for preparing silicon-carbon anode materials, the method operation steps are complicated, the reaction process is not easy to control, and the stability is poor, which is not obvious for improving the volume expansion of silicon during charging and discharging.

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