Method for preparing silicon-carbon composite negative material by low-temperature plasmas

Abstract

The invention discloses a method for preparing a silicon-carbon composite negative material by low-temperature plasmas. The method comprises the following steps: preparing a nanometer silicon complex:adding nanometer silicon, a silane coupling agent, an additive and a catalyst into an organic solvent, uniformly mixing and stirring the components, and carrying out low-temperature plasma treatment,ultrasonic dispersion, chemical vapor deposition and surface modification to obtain the silicon-carbon composite negative material. The method has the beneficial effects that the silane coupling agent and the catalyst are treated with the low-temperature plasma technology to generate charged particles and active components for acting on the nano silicon, and then the nano silicon / silicon monoxidecomposite material is obtained through carbonization and reduction; and the composite material has the characteristics of being high in specific capacity, high in structural stability, high in consistency and the like, so that the cycle performance of the material is improved.

Description

technical field [0001] The invention relates to the technical field of battery materials, in particular to a method for preparing a silicon-carbon composite negative electrode material by low-temperature plasma. Background technique [0002] As the Ministry of Finance announced the "Notice on Financial Support Policies for the Promotion and Application of New Energy Vehicles from 2016 to 2020", lithium-ion batteries are required to have higher energy density to meet the highest subsidy standards. The currently marketed lithium-ion battery anode materials are mainly graphite, which has a low specific capacity and is difficult to meet the demand for high specific energy density. Silicon-carbon anode materials have attracted the attention of researchers due to their high gram capacity and abundant resources, and have been used in high specific energy density lithium-ion batteries and other fields. However, their high expansion rate and conductivity deviation restrict their wide...

AI Technical Summary

Problems solved by technology

The currently marketed lithium-ion battery anode materials are mainly graphite, which has a low specific capacity and is difficult to meet the demand for high specific energy density.

Silicon-carbon anode materials have attracted the attention of researchers due to their high gram capacity and abundant resources, and are used in high specific energy density lithium-ion batteries and other fields, but their high expansion rate and conductivity deviation restrict their wide application.

[0003] At present, the preparation methods of silicon-carbon anode materials mainly include solid-phase method, liquid-phase method, and vapor-phase deposition method to improve the expansion of silicon-carbon anode materials and improve their cycle performance. However, silicon materials and carbon materials in silicon-carbon composite materials are produced through physical interaction. Combined together, resulting in limited improvement in its cycle performance, while its preparation process is complicated and the cycle is long, resulting in high manufacturing costs

For example, the patent (Application No. 201710872837.9) discloses the preparation method of silicon-carbon composite materials and their application as anode materials for lithium-ion batteries. As a reducing agent, low-temperature molten salt is used as a medium to realize the reduction of metal powder to silicon dioxide in a heat treatment process at a certain temperature to prepare porous elemental silicon. Although the silicon-carbon material prepared by it has improved specific capacity and cycle performance Improvement, but its range is not large, the preparation efficiency is low, and the preparation process is difficult to control accurately

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