Space buffer lithium-doped silicon oxide composite material, preparation method of composite material and lithium ion battery

Abstract

The invention relates to a space buffer lithium-doped silicon oxide composite material, a preparation method of the composite material and a lithium ion battery, and belongs to the technical field ofthe lithium ion battery. The material is of a core shell structure; the core is a lithium predoped silicon oxide composite material; the shell is a coated with carbon layer. For the doped lithium, silicon oxide in the silicon oxide composite material is converted into lithium silicate through solid phase reaction in the preparation process. The preparation method of the space buffer lithium-dopedsilicon oxide composite material comprises the steps that after a lithium source is covered on the silicon oxide particle surface, a coating carbon layer is formed at the obtained particle surface through chemical vapor carbon deposition; the obtained coated material is sintered in vacuum or inert atmosphere; a surface coated lithium source reacts with silicon oxide; on one hand, the lithium doping of the silicon oxide material is realized; on the other hand, the building of a cavity structure is realized. The space buffer lithium-doped silicon oxide composite material has the characteristicsof high specific capacity, high first-time charging and discharging efficiency and long service life.

Description

technical field [0001] The invention relates to a space-buffering, lithium-doped silicon oxide composite material, a preparation method thereof, and a lithium-ion battery, belonging to the technical field of lithium-ion batteries. Background technique [0002] With the increasing application range of lithium-ion batteries in different fields, people put forward higher requirements for the performance of lithium-ion batteries. In particular, many application fields have higher and higher requirements for the energy density of lithium-ion batteries. Whether it is 3C products or electric vehicles, people expect the energy density of batteries to reach a new order of magnitude, making the battery life or The cruising range is no longer the main factor that plagues the product. However, it is becoming more and more difficult to increase the energy density of current lithium-ion batteries, and energy density has become the biggest bottleneck restricting the development of current...

AI Technical Summary

Problems solved by technology

However, silicon oxide materials are currently facing two problems: the first is the high volume expansion during the lithiation process, which can reach 200%; the high volume expansion will inevitably lead to material failure, interface degradation and cycle performance decline.

This method solves the defects of high expansion and low first effect of silicon oxide from the material scale, but the lack of internal buffer structure makes the material still face the problems of interface instability and poor circulation in the process of volume expansion and contraction

Images