Preparation method of multi-modified silicon-manganese alloy composite negative electrode material

Abstract

The invention relates to a preparation method of a multi-modified silicon-manganese alloy composite negative electrode material, which comprises the following steps: mixing silicon powder, manganese powder and a ball milling medium, and carrying out ball milling to obtain a silicon-manganese alloy; adding deionized water into the silicon-manganese alloy to dilute, drying and granulating to obtainsilicon-manganese alloy powder; carrying out crystallization treatment on the silicon-manganese alloy powder, introducing a mixed gas of argon and oxygen, heating, carrying out heat preservation treatment, and cooling to room temperature; and adding asphalt and a conductive agent into the cooled silicon-manganese alloy powder, fully and uniformly mixing to obtain a precursor of the silicon-manganese alloy composite negative electrode material, and pyrolyzing the precursor in an argon atmosphere to obtain the multi-modified silicon-manganese alloy composite negative electrode material. The negative electrode material prepared by the method has excellent initial discharge specific capacity, initial charge-discharge efficiency and cycling stability, and the preparation method is simple, shortin preparation period, low in raw material cost and suitable for large-scale industrial production.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a preparation method of a multiple-modified silicon-manganese alloy composite negative electrode material. Background technique [0002] The field of new energy vehicle power batteries has high requirements on the energy density and service life of lithium-ion batteries. The theoretical specific capacity of traditional graphite anode materials is only 372mAh / g, which is far from meeting the increasing energy density requirements of lithium-ion batteries. Silicon has a high theoretical capacity (4200mAh / g) and is regarded as the most promising new negative electrode material, but its huge volume expansion effect during charging and discharging will make its capacity rapidly decay and reduce the battery life. production application. [0003] The current silicon-based anode materials generally have problems such as low initial charge and discharge efficien...

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Problems solved by technology

[0002] The field of new energy vehicle power batteries has high requirements on the energy density and service life of lithium-ion batteries. The theoretical specific capacity of traditional graphite anode materials is only 372mAh / g, which is far from meeting the increasing energy density requirements of lithium-ion batteries.

Silicon has a high theoretical capacity (4200mAh / g) and is regarded as the most promising new negative electrode material, but its huge volume expansion effect during charging and discharging will make its capacity rapidly decay and reduce the battery life. production application

[0003] The current silicon-based anode materials generally have problems such as low initial charge and discharge efficiency, large volume expansion, slow initial efficiency improvement, and rapid capacity decay. Many existing modification methods use carbon coating to form a core-shell structure to buffer volume changes. , but although the effect is improved only by carbon coating, it is far from meeting the actual use requirements, and the electrochemical performance needs to be further improved

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