含碳纳米管导电剂改善LiCoO2电极电化学性能

Carbon nanotubes containing conductive additives to improve the electrochemical performance of LiCoO_2 cathode

采用多壁碳纳米管(MWCNTs)和片状石墨(FNG)的复合物作导电剂来改善LiCoO2电极的电化学性能,并用恒电流充放电和扫描电子显微镜(SEM)对这种含MWCNTs的LiCoO2电极进行了研究。结果表明,复合物导电剂提高了LiCoO2电极的电化学性能。MWCNTs/FNG质量比为5的复合物(FNG-MWCNTs)作导电剂,LiCoO2电极的0.2C首次放电容量约为154.2mAh/g。和单纯的MWCNTs作导电剂相比,FNGMWCNTs作导电剂,LiCoO2电极有好的倍率放电性能,在3C倍率放电电压更高,放电比容量更高。原因可能如下:首先,MWCNTs、FNG和Li-CoO2颗粒三者实现了均匀的分散;其次,MWCNTs把多个孤立的FNG联系起来,形成了更为有效的导电通道。

The mixture of Mmulti-walled carbon nanotubes （MWCNTs） and flake natural graphite （FNG） is evaluated as a conductive additive to improve the electrochemical performance of LiCoO2 cathode. The MWCNTs containing LiCoO2 cathodes were characterized by current constant charge and discharge tests and scanning electron microscope （SEM）. The results indicate that the electrochemical performance of LiCoO2 cathode was improved by using the mixture of FNG and MWCNTs as a conductive additive. The initial discharged capacity of LiCoO2 cathode is 154.2mAh/g at 0.2C when the weight ratio of MWCNTs/FNG is 5. Compared with single MWCNTs loaded LiCoO2 cathode, mixture loaded LiCoO2 cathode has good rate discharge capacity. In addition, mixture loaded cathode has higher discharge voltage and higher discharged capacity at a rate of 3 C. The reason may be as followed： Firstly of all, MWCNTs, FNG, and LiCoO2 particles are uniformly dispersed; secondly, uniformly dispersed MWCNTs connected isolated FNG and the valid conducting networks were formed.