A kind of crystalline/amorphous silicon-carbon nanowire and its preparation method and application

Abstract

The invention discloses a crystal / amorphous silicon-carbon nanowire as well as a preparation method and application thereof, which belong to the field of lithium ion batteries. A crystal silicon core,an amorphous silicon layer and a carbon outer layer collectively form a three-layer structural composite material system: the crystal silicon core mainly plays a supporting effect; the amorphous silicon plays a role in storing the lithium; and the carbon is arranged at the outermost layer and plays a role in stabilizing an SEI membrane and increasing the coulombic efficiency. The crystal / amorphous silicon-carbon nanowire has the characteristics that the crystal / amorphous silicon nanowire is further prepared by utilizing the high temperature and instant cooling characteristics of thermal plasma; and meanwhile, the electrodeless heating characteristics of the thermal plasma ensure the high purity of products. The method is simple in process, environment-friendly in process, low in cost, continuous, controllable, and capable of realizing macro preparation. The crystal / amorphous silicon-carbon nanowire prepared by the invention is used as a lithium ion battery cathode, so that the volumechange is small in the lithium embedding / removing process, the structure is stable, and the energy density and cycling stability of the lithium ion battery cathode material can be effectively improved.

Description

technical field [0001] The invention relates to a lithium-ion battery negative electrode material, a preparation method and an application, and belongs to the field of lithium-ion batteries. Specifically, it relates to a crystalline / amorphous silicon-carbon nanowire gradient buffer composite material with high specific capacity and high coulombic efficiency that can be used as a lithium-ion battery negative electrode and its preparation method and application. Background technique [0002] The rapid development of portable electronic products and new energy vehicles has put forward higher requirements on the energy density of lithium-ion batteries. The lower theoretical specific capacity of traditional graphite anode (372mA h g -1 ) has been difficult to meet the demand for energy density of lithium batteries. Silicon anode materials have high theoretical lithium storage specific capacity (4200mAhg -1 ) and low lithium intercalation potential (~0.2V), it is considered to ...

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Problems solved by technology

Moreover, these preparation methods mainly use silane or silicon tetrachloride as the silicon source, and there are common problems such as high raw material cost, complicated preparation process, high equipment requirements, harsh process conditions, serious pollution, and difficulty in large-scale production.

And in the preparation process, metal particles are usually used as catalysts, which brings pollution to the material and reduces the specific capacity of the composite material.

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