Preparation method of N-doped coated graphene micron silicon composite material

Abstract

The invention relates to a preparation method of an N-doped graphene coated micron silicon composite material, in particular relates to a preparation method of a lithium ion battery cathode material, and provides the preparation method of an N-doped graphene and micron silicon composite material. The preparation method comprises the following steps: preparing oxidized graphene; preparing an oxidized graphene coated micron silicon composite material, that is, adding water to the oxidized graphene to prepare solution, adding micron silicon particles to the solution, carrying out ultrasound and mechanical agitation on the solution to obtain micron silicon and graphene mixed solution, carrying out freeze drying or spray drying on the micron silicon and graphene mixed solution to obtain oxidized graphene / micron silicon composite material; preparing N-doped graphene and micron silicon composite material, that is, placing the oxidized graphene / micron silicon composite material in a high-pressure reaction kettle, adding hydrazine hydrate, sealing to react, and drying to obtain the N-doped graphene and micron silicon composite material. The preparation method is used for preparing the lithium ion battery cathode material.

Description

technical field [0001] The invention relates to a method for preparing a negative electrode material of a lithium ion battery. Background technique [0002] Energy is the source of world development and human survival and progress. With the rapid development of science and technology, traditional fossil energy has been over-exploited and utilized, accompanied by the continuous discharge of pollutants such as polluted gases to the surrounding environment, and various ecological environments such as smog. The pollution problem has begun to sound the alarm to human beings, and it is urgent to develop new clean and green new energy sources. Various energy storage batteries such as fuel cells, solar cells, and lithium-ion batteries have begun to receive great attention. Among the many secondary batteries, lithium-ion batteries have the advantages of high energy density, no memory effect, less environmental pollution, and low cost. , has been widely used commercially, and has als...

AI Technical Summary

Problems solved by technology

Many studies have proved that when the size of silicon particles is reduced to micron or nanoscale, the electrochemical performance is significantly improved, but there are still some problems to be solved in the research and filling of graphene and silicon composite materials: first, from the perspective of scientific research, the research on silicon and graphene The research on composite materials is almost all focused on nano-silicon and graphene composite materials, and there is a lack of systematic understanding of the size effect of silicon on the performance of composite materials; there is a lack of systematic research on the physical structure and chemical modification of graphene on the performance of composite materials; about The understanding of how graphene regulates the solid electrolyte membrane (SEI) during charge and discharge of composite materials is almost blank

Secondly, from the perspective of industrial application, the real application of silicon and graphene composite materials as lithium-ion battery negative electrodes still faces the following problems. The first Coulombic efficiency of silicon and graphene composite materials is far from meeting the requirements of industrial production (negative electrode The material requirement is more than 85%); the cycle performance of the second composite material needs to be further improved; moreover, parameters such as the tap density of the composite material of nano-silicon and graphene have not yet reached the requirements of industrialized production

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