锂离子电池硅/石墨/蔗糖碳复合负极材料的制备和电化学性能

Preparation of Si/Graphite/Sucrose-Carbon Composite Material and its Electrochemical Property as Anode for Lithium-ion Battery

以纳米硅(Si)、天然石墨(NG)和蔗糖为前驱体通过球磨和裂解制备了具有壳核结构的碳硅复合材料(Si/NG/DC).用X射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)表征了复合材料的组成和形貌结构.恒电流充放电测试表明,Si/NG/DC复合材料表现出较好的电化学性能,它的最高可逆容量达730mA.h.g-1,在测试的45个循环中,从第二个循环开始,容量没有出现明显衰退.交流阻抗(EIS)测试表明,Si/NG/DC导电性的提高和电极结构在循环过程中的稳定性是其电化学性能改善的原因.

Core-shell Si/NG/DC composite material comprising silicon （Si）, natural graphite （NG） and sucrose- based disordered carbon （DC） , was synthesized by high energy ball milling and pyrolysis, using silicon, graphite and sucrose as precursors. X-ray diffraction （XRD） , scanning electron microscope （SEM） and transmission elec- tron microscope （TEM） were used to characterize the compositions and morphology of the composite. Galvanostatic charge-discharge technique measurement shows that Si/NG/DC composite exhibits excellent electrochemical per- formance. Its highest reversible capacity is as high as 730 mA·h·g-1. In the tested 45 cycles, no obvious capacity fading is observed from the second cycle. Electrochemical impedance spectroscopy （E/S） measurement demon- strates that the improvement of Si/NG/DC in cyclic performance should be attributed to the enhancement of its con- ductivity and the stability of its microstructure during cycling.