Carbon nanotube/graphene/silicon composite lithium battery negative electrode material and preparation method therefor

Abstract

The invention belongs to the technical field of an energy material, and provides a carbon nanotube/graphene/silicon composite lithium battery negative electrode material and a preparation method therefor, for overcoming the shortcoming of poor electric circulation performance caused by severe volume effect of a silicon negative electrode in an electrochemical lithium storage process, difficulty in forming a stable surface solid electrolyte film and low intrinsic conductivity. The composite lithium battery negative electrode material comprises foamed nickel, and a graphene layer and a silicon co-mixed carbon nanotube layer which are alternately arranged on the foamed nickel; the graphene layer in on the uppermost layer; and the graphene layer on the uppermost layer is also covered with a thick graphene protection layer. By adoption of the multi-layer structure of the graphene layer and the alternate silicon/carbon nanotube composite layer, three-dimensional compounding on silicon power is performed based on high mechanical performance and high conductivity of the graphene and the carbon nanotubes jointly, so that the negative electrode rate capability and cycling performance are remarkably improved under the premise of maintaining high silicon specific capacity; and meanwhile, the preparation method has the advantages of simple process, low cost and high repeatability.

Description

technical field [0001] The invention belongs to the technical field of energy materials and relates to a lithium battery negative electrode material, in particular to a carbon nanotube / graphene / silicon composite lithium battery negative electrode material and a preparation method thereof. Background technique [0002] Nowadays, with the development and progress of modern society, the supply and utilization of energy are indispensable. Worldwide energy shortage has become one of the urgent problems to be solved in the 21st century. For this reason, many researchers have been working on finding other green energy sources that can replace non-renewable fossil fuels, such as solar energy, wind energy, hydropower and so on. Unlike traditional fossil fuels, most of these green energy sources have uncontrollable and intermittent problems, so the storage and utilization of these energy sources will increase the cost; this also makes researchers pay attention to new energy storage sy...

AI Technical Summary

Problems solved by technology

However, if it is to be applied in the field of large-scale high-power systems such as plug-in hybrid electric vehicles (PHEV) or plug-in electric vehicles (PEV), the performance requirements for lithium-ion batteries have also been greatly improved, especially in terms of energy density. In terms of cycle life and safety issues, the materials and systems of lithium-ion batteries have yet to be further developed and improved.

Among various non-carbon anode materials, silicon has attracted the attention of more and more researchers with its unique advantages and potential; the theoretical lithium storage capacity of silicon is as high as 4200mAh g -1 , more than 10 times the capacity of graphite, the voltage platform of silicon is slightly higher than that of graphite, it is difficult to cause the phenomenon of lithium precipitation on the surface during charging, and its safety performance is better than that of graphite anode materials; in addition, silicon is one of the most abundant elements in the earth's crust. Wide range of sources and low price; however, there are still many problems with silicon as the negative electrode of next-generation lithium-ion batteries: First, in the process of electrochemical lithium storage, silicon ato

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