Mesoporous silicon/cobalt disilicide composite microsphere material as well as preparation method and application thereof

Abstract

The invention discloses a mesoporous silicon / cobalt disilicide composite microsphere material as well as a preparation method and application thereof. The method comprises the following steps: sequentially adding ammonia water and an ethyl orthosilicate ethanol solution into a cobalt nitrate ethanol solution under stirring to prepare a precursor, performing reduction on the obtained precursor by adopting a magnesiothermic process, and finally washing the reduced product by using hydrochloric acid. When the mesoporous silicon / cobalt disilicide composite microspheres provided by the invention are used for preparing a negative electrode material of a lithium ion battery, the cobalt disilicide component and the mesoporous structure of the composite microspheres facilitate suppressing materialpowdering and improving electrode reaction kinetics, so that the actual capacity, cycle performance and high rate performance of the material are effectively improved.

Description

technical field [0001] The invention relates to the field of lithium ion battery electrode materials, in particular to a mesoporous silicon / cobalt disilicide composite microsphere material and its preparation method and application. Background technique [0002] Due to the advantages of high energy density, high power density and long cycle life, lithium-ion batteries have occupied a dominant position in the field of secondary batteries, and have been successfully used in portable electronic products, electric vehicles, and battery energy storage power stations. However, the performance of graphite carbon anode materials used in traditional lithium-ion batteries has reached a bottleneck that is difficult to break through, seriously restricting the development of new energy sources. It has become the focus of current research to develop alternative anode materials with high specific capacity and high safety and promote their practical application. [0003] New silicon-based ...

AI Technical Summary

Problems solved by technology

However, silicon-based anode materials still have shortcomings such as low actual capacity, poor cycle performance, and poor high-rate performance.

Silicon is a semiconductor material with poor conductivity. It does not have the layered structure of graphite. Its lithium storage mechanism is based on the reversible alloying / dealloying reaction between silicon and lithium, accompanied by a volume change of more than 300%. On the one hand, it leads to the pulverization and shedding of electrode materials, resulting in the reduction of active materials, and on the other hand, it also leads to the rupture and reformation of SEI film, resulting in the continuous consumption of lithium ions and electrolyte, and also increases the electrode impedance.

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