Preparation method of multi-element polyphase composite lithium ion battery negative material

Abstract

The invention discloses a preparation method of a multi-element polyphase composite lithium ion battery negative material. The method is characterized in that ball milling of metal oxide, a silicon-based material, lithium hydride and CO2 gas is carried out to obtain the multi-element polyphase composite material; and the silicon-based material and lithium hydride cannot be added after the CO2 gas. The metal oxide is compounded with the silicon-based material and are pre-lithiated in the ball milling process of the metal oxide, the silicon-based material and lithium hydride, the CO2 gas chemically reacts with the above obtained pre-lithiated product to form a protection layer on the surface of the pre-lithiated product, and the obtained multi-element polyphase composite material has the advantages of high reversible capacity, long cycle life and high initial coulomb efficiency as a lithium ion battery negative electrode; and electrodes can be directly produced by using an aqueous binder in air through adopting a smearing technology, so the negative material is convenient for popularization and application.

Description

technical field [0001] The invention relates to the field of lithium-ion battery negative electrode materials, in particular to a preparation method of multi-element multi-phase composite lithium-ion battery negative electrode materials. Background technique [0002] As a new type of chemical power source, lithium-ion batteries are widely used in the field of portable mobile electronic devices, power tools, Energy storage devices, electric vehicles and hybrid vehicles are widely used. Especially in recent years, the rapid development of electric vehicles and the miniaturization and lightening of electronic equipment have put forward higher requirements for lithium-ion batteries. The development of new lithium-ion batteries that are safe, efficient, high-capacity, high-rate, and long-cycle life has become the current The research hotspot, and the electrode material is the decisive factor that determines the performance of lithium-ion batteries, and it is also the difficulty ...

AI Technical Summary

Problems solved by technology

The theoretical capacity of most metal oxide anode materials is generally above 700 mAh per gram, the volume expansion is smaller than that of silicon materials, and the cycle stability is better than that of silicon materials, but due to the formation of amorphous Li in the first discharge process 2 O and SEI film, in the subsequent charging process, these Li 2 Not all O is reversible, and the SEI film is also partially decomposed, resulting in a large loss of the first irreversible capacity of the metal oxide, and a low first coulombic efficiency, and the first coulombic efficiency of the unmodified oxide is between 50% and 70%.

[0004] Silicon materials and metal oxides alone have been studied as anode materials for lithium-ion batteries, especially nanometerization, but the preparation process is complicated and the cost is high, so that nanomaterials cannot be commercialized.

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