Preparation method of nitrogen-doped ordered porous carbon coated silicon nanometer composite material

Abstract

The invention discloses a preparation method of a nitrogen-doped ordered porous carbon coated silicon nanometer composite material. The preparation method comprises the following steps: firstly adopting dopamine hydrochloride coated silicon nanometer particles, then using cobaltous acetate for catalysis treatment, and finally carrying out high-temperature calcinations to obtain the target product. The preparation method of the composite material disclosed by the invention is simple, the obtained product is good in cycle stability and cycle specific capacity, and the composite material can serve as an excellent negative electrode material for lithium ion batteries.

Description

technical field [0001] The invention relates to a nitrogen-doped ordered porous carbon-coated silicon nanocomposite material and a preparation method thereof, belonging to the field of porous nanomaterials. Background technique [0002] Lithium-ion batteries have large capacity, high working voltage, low self-discharge, high safety, long cycle life, no memory effect, small size, light weight, high specific energy, and do not contain heavy metal harmful substances such as cadmium, lead, and mercury , so there will be no such environmental pollution. In recent years, the rapid development of portable electronic devices, electric tools and electric vehicles has put forward higher requirements on the performance of lithium-ion batteries, which has stimulated the research of a new generation of lithium-ion battery anode materials with high specific capacity and long cycle life. At present, the lithium-ion battery anode materials used on a large scale in the market are mainly gra...

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Problems solved by technology

However, during the process of lithiation, the volume of silicon becomes three times that of the original volume, and the expansion force generated by the increase in volume will destroy the physical structure of the electrode, resulting in electrode destruction and a decrease in the activity of the material, resulting in a significant decrease in the specific capacity of the silicon electrode.

Due to the volume effect of silicon electrodes, it is difficult to form a stable solid electrolyte film (SEI) on the surface of silicon materials

The physical structure of the electrode is destroyed, and a new SEI film will continue to form on the new silicon surface of the electrode, so the charging / discharging efficiency of the battery will be reduced, and the decay rate of the battery capacity will be accelerated

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