Silicon-carbon composite negative electrode material, negative electrode plate, preparation method thereof and lithium-ion battery

Abstract

The invention belongs to the field of new energy materials, and relates to a silicon-carbon composite negative electrode material, a negative electrode plate, a preparation method thereof and a lithium-ion battery. The preparation method of the silicon-carbon composite negative electrode material comprises the following steps: S1, dispersing phenol and / or aminophenol, formaldehyde and a silicon precursor material into an alcohol-amine mixed aqueous solution, violently stirring and reacting at 20-90 DEG C for at least 20 minutes, carrying out solid-liquid separation, and drying to obtain a silicon dioxide / phenolic aldehyde compound with a fractal structure; and S2, roasting the silicon dioxide / phenolic aldehyde compound in the presence of magnesium powder and / or aluminum powder to obtain the silicon-carbon composite material with the fractal structure. When the silicon-carbon composite material is used as a lithium-ion battery negative electrode material, the failure caused by volume change in the charging and discharging process can be well overcome, a good conductive network is maintained, the volume expansion is reduced, the first reversible capacity and the first coulombic efficiency are improved, the first cycle capacity loss is reduced, and the cycle stability is improved.

Description

technical field [0001] The invention belongs to the field of new energy materials, and in particular relates to a silicon-carbon composite negative electrode material, a negative electrode sheet, a preparation method thereof, and a lithium ion battery. Background technique [0002] At present, with the development of the new energy industry and the intensification of environmental pollution, the development of electric vehicles is becoming more and more rapid, and lithium-ion batteries with high capacity, high power and long cycle life have become urgently important. Lithium-ion batteries are the core of new energy vehicles and energy storage technologies at this stage, and the electrochemical performance of lithium-ion batteries mainly depends on the positive and negative electrodes of the battery. The key to lithium-ion batteries. Cathode materials have been extensively studied, and anode materials have also received more and more attention. Conventional lithium-ion batt...

AI Technical Summary

Problems solved by technology

However, due to the severe volume expansion (volume expansion of about 400%) of silicon materials during charge and discharge, the cycle performance of lithium-ion batteries is very poor.

In order to alleviate the volume expansion of silicon materials, silicon-carbon composite materials have been developed, and carbon is used to coat and modify silicon-based materials. However, the electrochemical performance and cycle life of existing silicon-carbon composite materials still need to be improved.

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