Composite silicon-based negative electrode material, preparation method thereof and lithium ion battery

• Main Authors: WAN YUANXIN, KONG LINGYONG, REN WANGBAO, ZHONG ZEQIN, CHEN CAIFENG
• Format: Patent
• Language: Chinese; English
• Published: 05.03.2021
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY

The invention discloses a composite silicon-based negative electrode material, a preparation method thereof and a lithium ion battery. The composite silicon-based negative electrode material is of a core-shell structure, and the core-shell structure comprises a core body, a first shell layer coating the core body and a second shell layer coating the first shell layer; wherein the material of the core body comprises a silicon negative electrode material, the material of the first shell layer comprises a pre-lithiated material, and the material of the second shell layer comprises carbon. The composite silicon-based negative electrode material has the advantages of low initial coulombic efficiency, low internal resistance, high double-shell mechanical properties, effective inhibition of the volume expansion of the silicon-based negative electrode material, maintenance of the structural stability in the charging and discharging process, and excellent cycle performance. And moreover, the process conditions are eas