Preparing method of nanometer silicon particles for lithium battery

Abstract

The invention discloses a preparing method of nanometer silicon particles which are doped with trace elements and used for a lithium battery. The doped trace elements are N-type doped crystalline silicon and P-type doped crystalline silicon. The preparing method comprises the steps that firstly, the N-type doped crystalline silicon and the P-type doped crystalline silicon serve as raw materials, acopper pipe serves as a working electrode, a pulse discharge method is adopted for preparing the micron / sub-micron silicon particles doped with the trace elements, and the intrinsic conductivity of silicon is increased by doping the trace elements. Afterwards, the prepared micron / sub-micron silicon particles doped with the trace elements are further nanocrystallized through a high-energy ball milling method, so that the absolute volume change of the silicon particles is reduced. By means of the method, the circulation performance of the silicon material can be improved. The method is simple in preparing technology, convenient to operate and low in cost, and expanded production is facilitated.

Description

technical field [0001] The invention relates to the field of nano material preparation and new energy, in particular to a preparation method of nano-silicon particles for lithium batteries doped with trace elements. Background technique [0002] Lithium-ion batteries are widely used as power sources for portable consumer electronics (mobile phones, laptops, cameras, etc.) due to their high energy density, safety, environmental protection, and long life. In recent years, the development of pure electric vehicles, plug-in hybrid electric vehicles and large-scale distributed energy storage power stations has put forward higher requirements for the energy density, safety and cycle stability of lithium-ion batteries. The main ways to improve the energy density of lithium-ion batteries include the development of positive / negative electrode materials with high specific capacity and the development of high-voltage positive electrode materials. In terms of negative electrodes, the t...

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Problems solved by technology

[0003] Although silicon-based anode materials have significant advantages, similar to other high specific capacity anodes, the disadvantages of silicon materials are also very prominent: first, silicon has a severe volume effect (volume change greater than 300%) during charge / discharge, and the material The continuous shrinkage / expansion of the volume easily leads to the pulverization of material particles, the dynamic reconstruction of the solid electrolyte membrane, and the loss of the conductive environment inside the electrode, which eventually leads to a sharp decline in capacity; secondly, the conductivity of silicon is low

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