Preparation method of composite nano silicon negative electrode material based on conductive carbon aerogel and product thereof

Abstract

The invention discloses a preparation method of a composite nano silicon negative electrode material based on conductive carbon aerogel and a product thereof, and the preparation method comprises the following steps of: (1) dissolving pretreated waste biomass and a fiber additive in an aqueous solution of an alkaline substance together, and performing stirring to obtain reticular solid gel; (2) drying the reticular solid gel, and performing screening to obtain a carbon aerogel precursor; (3) taking a gaseous silicon source and the carbon aerogel precursor as raw materials, and carrying out a chemical vapor deposition process to prepare a compound of carbon aerogel and nano silicon; and (4) blending the compound of the carbon aerogel and the nano silicon with a carbon source, and conducting heating and carbonizing to obtain the composite nano silicon negative electrode material based on the conductive carbon aerogel. According to the preparation method disclosed by the invention, the waste biomass is used as the raw material, the cost is low, the prepared negative electrode material is high in strength and good in conductivity, and the assembled battery has a relatively high first effect.

Description

technical field [0001] The invention relates to the field of negative electrode materials for batteries, in particular to a preparation method and products thereof based on conductive carbon airgel composite nano-silicon negative electrode materials. Background technique [0002] Current state-of-the-art lithium-ion batteries are no longer sufficient to meet the growing demands of electric vehicles and large-scale energy batteries. Silicon is considered the most promising candidate to replace graphite. It is the second most abundant element in the earth's crust, is environmentally friendly, and has a super high theoretical capacity (4200mAh / g). However, during cycling, the volume of silicon particles rapidly expands and contracts with the intercalation and delamination of lithium ions (Li-ions). This drastic volume change leads to pulverization of silicon particles, destruction of silicon-based electrodes, and repeated regeneration of the solid electrolyte interfacial laye...

AI Technical Summary

Problems solved by technology

[0006] This technical scheme combines the high specific surface area of ​​carbon airgel and the excellent conductivity of graphene to prepare composite negative electrode materials. Airgel and nano-silicon liquid are mixed for hydrothermal reaction. Since the hydrothermal reaction is carried out under high temperature and high pressure, the gas and liquid raw materials are always in a boiling state, which will easily lead to the collapse of carbon aerogel, and is not conducive to the synthesis of silicon and carbon gas. compounding of gel

In addition, due to the evacuation of graphene properties, the CA / nano-silicon composite material cannot be well wrapped, and there is a risk of direct contact between silicon and electrolyte during charging and discharging, which will consume capacity and cause irreversible damage

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