Cui Li-Feng, Yang Yuan, Hsu Ching-Mei, Cui Yi
Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
Nano Lett. 2009 Sep;9(9):3370-4. doi: 10.1021/nl901670t.
We introduce a novel design of carbon-silicon core-shell nanowires for high power and long life lithium battery electrodes. Amorphous silicon was coated onto carbon nanofibers to form a core-shell structure and the resulted core-shell nanowires showed great performance as anode material. Since carbon has a much smaller capacity compared to silicon, the carbon core experiences less structural stress or damage during lithium cycling and can function as a mechanical support and an efficient electron conducting pathway. These nanowires have a high charge storage capacity of approximately 2000 mAh/g and good cycling life. They also have a high Coulmbic efficiency of 90% for the first cycle and 98-99.6% for the following cycles. A full cell composed of LiCoO(2) cathode and carbon-silicon core-shell nanowire anode is also demonstrated. Significantly, using these core-shell nanowires we have obtained high mass loading and an area capacity of approximately 4 mAh/cm(2), which is comparable to commercial battery values.
我们介绍了一种用于高功率和长寿命锂电池电极的新型碳硅核壳纳米线设计。将非晶硅涂覆在碳纳米纤维上以形成核壳结构，所得的核壳纳米线作为阳极材料表现出优异的性能。由于碳的容量比硅小得多，碳核在锂循环过程中承受的结构应力或损伤较小，并且可以起到机械支撑和高效电子传导通道的作用。这些纳米线具有约2000 mAh/g的高电荷存储容量和良好的循环寿命。它们在第一个循环中的库仑效率为90%，在随后的循环中为98 - 99.6%。还展示了由LiCoO₂ 阴极和碳硅核壳纳米线阳极组成的全电池。值得注意的是，使用这些核壳纳米线，我们获得了高的质量负载和约4 mAh/cm² 的面积容量，这与商业电池的值相当。
