Silicon-based negative electrode material and preparation method thereof, lithium ion battery and electric appliance

Abstract

The invention discloses a silicon-based negative electrode material and a preparation method thereof, a lithium ion battery and an electric appliance and relates to the technical field of battery electrode material preparation. The preparation method of the silicon-based negative electrode material comprises the following steps: annealing a primary negative electrode material which is obtained by cold spraying and is loaded with a Si-Cu coating on the surface in an inert gas atmosphere at the temperature of 500-800 DEG C, and preserving heat for 7-9 hours. The silicon-based negative electrode material is prepared by the preparation method. The lithium ion battery adopts the silicon-based negative electrode material as a negative electrode. The electric appliance takes the lithium ion battery as a power supply. After the primary negative electrode material of the Si-Cu coating is obtained through cold spraying on the copper foil, the Si-Cu3Si-Cu composite material obtained through annealing treatment at the proper temperature and the proper heat preservation time is used as the negative electrode material of the lithium ion battery and has good cycle stability and reversible capacity.

Description

technical field [0001] The invention relates to the technical field of battery electrode material preparation, in particular to a silicon-based negative electrode material and a preparation method thereof, a lithium ion battery and an electrical appliance. Background technique [0002] With the increasingly prominent environmental and energy issues, it is urgent to develop new clean energy to replace old energy. The development and utilization of new energy must have corresponding energy storage equipment, so that it can be well applied to various industries. Lithium-ion batteries are considered to be one of the most promising energy storage devices at present. Lithium-ion batteries have the advantages of high specific energy, high safety performance, wide operating temperature range, and long storage life. They have not only been widely used in various small mobile devices, but are also very suitable as power sources for electric vehicles and large power reserves. . In p...

AI Technical Summary

Problems solved by technology

However, the disadvantages of silicon anode materials are also quite obvious, for example: (1) silicon anode materials will produce severe volume expansion (100% to 300%) during the process of lithium ion intercalation and deintercalation, and the huge volume effect will easily destroy the material structure , resulting in poor reversibility

(2) The solid electrolyte interface (SEI) film continuously grows / crushes on the new surface of the silicon anode, consumes a large amount of lithium ions, leads to a large irreversible capacity, and finally causes a decrease in the initial Coulombic efficiency

(3) The low conductivity of silicon leads to rapid degradation of the electrode, which also limits its development accordingly

However, since silicon is a semiconductor material, its own characteristics are brittle and hard, and its plastic deformation ability is not as good as that of metals, so the deposition rate is not as good as that of metals.

If the silicon-copper mixed powder is deposited on the substrate, because the deposition effect of the exposed silicon powder on the surface of the deposited layer on the copper substrate is not ideal, it is necessary to modify the surface of the silicon particle and the copper particle phase interface to prevent the The particle undergoes severe volume changes during cycling, resulting in the detachment of active silicon from the surface of the copper support matrix, and the long-term cycle performance is still unsatisfactory

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