Silicon-based negative electrode material for inhibiting crack formation in lithium intercalation and deintercalation process and preparation method of silicon-based negative electrode material

Abstract

The invention discloses a silicon-based negative electrode material for inhibiting crack formation in a lithium intercalation and deintercalation process and a preparation method of the silicon-based negative electrode material, the silicon-based negative electrode material is of a three-layer composite structure which sequentially comprises a silicon-based material layer, a perovskite coating layer and an amorphous carbon coating layer from inside to outside; the silicon-based material layer is doped with at least one element selected from B, P, Al, Zr, Ti and Mg; and the perovskite is LaMO3, and M = Co and / or Fe. According to the invention, the method of high-temperature sintering element doping, perovskite coating layer coating and carbon coating is adopted to inhibit the formation of cracks in the lithium intercalation and deintercalation process of the silicon-based negative electrode material, so that the huge stress change of the silicon-based negative electrode material in the lithium intercalation and deintercalation process is effectively relieved, and the formation of cracks in particles is inhibited; and relatively high first coulombic efficiency and excellent cycling stability are shown.

Description

technical field [0001] The invention relates to the technical field of designing lithium-ion battery materials, in particular to a silicon-based negative electrode material and a preparation method thereof that suppress crack formation during lithium intercalation and extraction. Background technique [0002] With the development of lithium-ion batteries to large-scale applications such as electric vehicles and renewable energy storage systems, people's demands on the performance of lithium-ion batteries are also increasing, and performance indicators such as energy density and power density of primary lithium-ion batteries need to be further improved. In terms of negative electrode materials, traditional graphite carbon negative electrode materials have limited specific capacity, which has been difficult to meet the needs of high energy density batteries. At present, the anode materials with high energy density that are mainly developed commercially are mainly silicon-based...

AI Technical Summary

Problems solved by technology

[0006] During the cycle of ternary materials, due to the accumulation of stress, cracks will be generated inside the secondary particles, resulting in poor structural stability of ternary materials. Doping technology is an important method to solve the poor structural stability of ternary materials.

Based on the problem of cracks existing in the charging and discharging process of silicon-based negative electrode materials in the background technology, the present invention proposes a silicon-based negative electrode material that suppresses crack formation during lithium intercalation and desorption and a preparation method thereof, and relieves silicon-based negative electrode materials through element doping protection. The internal stress of the negative electrode material, with the help of the perovskite coating layer and the carbon coating layer, jointly inhibits the formation of cracks during the lithium insertion and extraction process, thereby improving the cycle life of the material

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