All-solid-state lithium ion battery silicon negative electrode material and preparation method thereof

Abstract

The invention discloses an all-solid-state lithium ion battery silicon negative electrode material and a preparation method thereof, and relates to the technical field of lithium ion battery negativeelectrode materials. The all-solid-state lithium ion battery silicon negative electrode material comprises a negative electrode material core and a coating layer. The preparation method comprises thefollowing steps: preparing a graphene dispersion liquid; dispersing to obtain a paper fiber turbid liquid; preparing graphene conductive paper; preparing a graphene oily dispersion liquid; and obtaining the all-solid-state lithium ion battery silicon negative electrode material. In the invention, a graphene coating layer having good compatibility with a solid electrolyte is adopted; a volume change of an active substance in contact with the solid electrolyte is favorably relieved; and problems of low initial coulombic efficiency and a large irreversible capacity can be overcome, a usage demandis satisfied. The preparation method of the all-solid-state lithium ion battery silicon negative electrode material is simple in process condition, controllable in preparation condition and suitablefor large-scale production and development.

Description

technical field [0001] The invention relates to the technical field of lithium ion battery negative electrode materials, in particular to an all-solid lithium ion battery silicon negative electrode material and a preparation method thereof. Background technique [0002] As a new generation of secondary batteries, lithium-ion batteries have been widely used in electric vehicles, energy storage grids, consumer electronics and other fields in recent years. The anode materials used in traditional commercial lithium-ion batteries are mainly graphite, and its theoretical specific capacity is only 372mAh / g, which cannot meet the current demand for high energy density storage devices. Silicon, as a kind of anode material for lithium-ion batteries, is considered to be one of the most potential high specific capacity anode materials. With a high specific capacity of 4200mAh / g, silicon is expected to replace graphite as a new generation of anode materials. [0003] At present, resear...

AI Technical Summary

Problems solved by technology

However, silicon, as the negative electrode material, has a serious volume change problem during the charging and discharging process. Such a huge volume change can easily lead to the pulverization and coating peeling off of the silicon negative electrode material on the electrode sheet, which affects the cycle life of the material. At the same time, due to the semiconducting nature of silicon, its conductivity is also poor, which is reflected in poor rate performance. There are problems of low first-time Coulombic efficiency and large irreversible capacity, which cannot meet the needs of use.

Therefore, for the practical application of lithium-ion batteries, silicon anode materials are still facing huge challenges, especially for the current promising all-solid-state lithium-ion batteries, the problem is even worse.