Silicon-carbon negative pole material for lithium ion battery and preparation method thereof

Abstract

The invention provides a silicon-carbon negative electrode material for a lithium ion battery. The silicon-carbon negative electrode material is prepared from the ingredients: nanometer silicon, a conductive agent and hard carbon, wherein the nanometer silicon is 5-20nm noncrystalline silicon, and the purity is greater than or equal to 99.9 percent; a carbon source of the hard carbon is biomass three-grade tar; the conductive agent is a battery grade conductive agent. The silicon-carbon material has the structure that nanometer silicon and the conductive agent form composite particles, and thecomposite particles are uniformly dispersed in the hard carbon material. For the negative electrode material for the lithium ion battery, the reversible capacity is 800 to 1000mAh / g; the primary effect is 81 to 85 percent; the 1C / 1C circulation of 1000 circle capacity retention ratio is higher than 80 percent. The invention also provides a preparation method of the silicon-carbon material. The method has the advantages that the preparation period is short; the process is clean; the process technology is mature; the industrial production is convenient.

Description

technical field [0001] The invention relates to a silicon-carbon negative electrode material and a preparation method thereof, in particular to its high capacity, low expansion, and long cycle characteristics as a negative electrode material for lithium-ion batteries, and the use of lignin tertiary tar as a raw material through polycondensation and crosslinking processes Preparation method of silicon carbon negative electrode. Background technique [0002] Silicon-carbon anode materials are currently one of the research hotspots in the field of lithium-ion batteries, and small-scale industrialized silicon-carbon materials have appeared both at home and abroad. The analysis found that these industrialized silicon-carbon materials have a common defect: poor cycle performance. [0003] The cycle performance of silicon-carbon materials is mainly related to the size of silicon, the dispersion of silicon, and the design of silicon-carbon structures. A single solution to one of th...

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Problems solved by technology

The analysis found that these industrialized silicon-carbon materials have a common defect: poor cycle performance

[0003] The cycle performance of silicon-carbon materials is mainly related to the size of silicon, the dispersion of silicon, and the design of silicon-carbon structures. A single solution to one of these factors cannot cure the cycle performance of silicon-carbon materials.

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