Preparation process of zinc oxide coated silicon negative electrode material

Abstract

The invention relates to the technical field of lithium ion battery negative electrode materials, and in particular relates to a preparation process of a zinc oxide coated silicon negative electrode material. The preparation process sequentially comprises the steps of 1) performing ball milling treatment on conductive agent graphene, a binder and silicon nanoparticles, adding deionized water, and uniformly stirring to obtain slurry; 2) coating the slurry on the surface of a current collector and then drying; 3) activating and melting zinc powder to obtain zinc in a molten state; and 4) after the porous aluminum foil negative electrode material coated with the graphene and the silicon nanoparticles is uniformly coated with zinc in the molten state, performing calcination treatment to obtain the zinc oxide coated silicon negative electrode material. The preparation process provided by the invention is simple and easy to implement, simple and convenient to operate and low in required cost, and the prepared zinc oxide coated silicon negative electrode material can effectively prevent the problem of volume expansion and shrinkage of silicon in the charge-discharge reaction process, inhibit side reaction of the negative electrode material and improve the stability and the cycle efficiency of electrode circulation, and has relatively high conductive performance.

Description

[0001] Original application number: 2018112446401 [0002] Date of original filing: October 24, 2018 [0003] Applicant of the original case: Dongguan Institute of Technology [0004] Title of original application: A preparation method of zinc oxide-coated silicon negative electrode material. technical field [0005] The invention relates to the technical field of negative electrode materials for lithium ion batteries, in particular to a preparation process for zinc oxide-coated silicon negative electrode materials. Background technique [0006] Since Japan developed the first lithium-ion battery in 1990, due to its high specific capacity, high working voltage, long cycle life, and no memory effect, lithium-ion batteries have penetrated into all aspects of people's lives, and communication equipment is inseparable. Opening it, transportation equipment also shows its use, especially with the miniaturization and flexible development of electronic products, the research and d...

AI Technical Summary

Problems solved by technology

[0007] In order to improve the energy density of lithium-ion batteries, people are eager to find new materials with higher specific capacity to replace the traditional materials of lithium-ion batteries. Silicon is the negative electrode material of lithium-ion batteries with the highest specific capacity (4200mAh / g) found so far. , is a negative electrode material with high potential, which can not only increase the capacity of the battery, but also reduce the load of the negative electrode material in the battery accordingly, thereby improving the energy and power density of the battery. Not only that, silicon is widely distributed in nature, Just lower than oxygen, the source is extremely abundant and the cost is low, but there are still some bottlenecks in silicon as the negative electrode material of lithium batteries. First, silicon will have the problem of volume expansion and contraction in the charge and discharge reaction, and its expansion can reach as high as 300%. Due to volume expansion, stress is generated inside the material and the structure of the material is destroyed, which leads to the fragmentation and pulverization of the material, which makes the compactness of the electrode coating material worse, and in severe cases, it will fall off. After falling off, it will be separated from the current collector. The charge-discharge reaction is difficult to continue, so the cycle stability and battery capacity of the battery are deeply affected

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