Method of producing silicon carbon negative pole material of lithium ion battery

Abstract

A preparation method of carbon / silicon cathode for ion lithium battery includes the procedures as follows: firstly a high-molecular polymer is used to treat the silicon powder with the nanometer fineness to form an electroconductive film over the surface of the silicon powder, secondly asphaltum as the adhesive is dissolved into an organic solvent, which is added into the silicon powder prepared in the step 1, mixed adequately and evenly, then added with spheric graphite, mixed evenly and then steamed to eliminate the solvent, to form a covering layer containing silicon on the surface of the spheric graphite, thirdly the material obtained in step 2 undergoes carbonization under the protection with the inert gas and, fourthly the asphaltum as the impregnant is dissolved into an organic solvent, and slowly added into the material obtained in step 3, which is mixed evenly and then steamed to eliminate the solvent, and the asphaltum as the impregnant is used to cover outside the silicon coverage layer, then the material obtained in step 4 undergoes carbonization under the protection with the inert gas to produce the final product. The present invention provides a preparation method of carbon / silicon cathode for ion lithium battery, which helps the active silicon carry out high capacity and is capable of good recycling efficacy at the same time.

Description

technical field [0001] The invention relates to a method for preparing a negative electrode material of a lithium ion battery, in particular to a method for preparing a silicon-carbon composite material. Background technique [0002] With the wide application and rapid development of various portable electronic devices and electric vehicles, people's demand and performance requirements for the power supply of various electrical products are also getting higher and higher. It has been successfully and widely used in the field of mobile electronic terminal equipment in the past ten years. [0003] At present, lithium transition metal oxide / graphite system is mostly used in commercial lithium-ion secondary batteries. Due to the low theoretical lithium storage capacity of the negative electrode itself in this battery system, it is difficult to meet people's increasing demand for battery capacity simply through process improvement. Therefore, the search for anode materials with ...

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Problems solved by technology

Graphite-silicon / Si(OCH 3 ) 4 Although the material has relatively stable mechanical properties, which is conducive to the improvement of cycle performance, on the other hand, the existence of Si-O network structure also hinders the diffusion behavior of lithium, which reduces the intercalation amount of lithium and cannot fully utilize the high performance of Si. Capacity characteristics (S.B.Ng, J.of Power Sourdes, 94(2001):63-67)