Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States.
Nano Lett. 2011 Jul 13;11(7):2949-54. doi: 10.1021/nl201470j. Epub 2011 Jun 14.
Silicon is a promising candidate for the anode material in lithium-ion batteries due to its high theoretical specific capacity. However, volume changes during cycling cause pulverization and capacity fade, and improving cycle life is a major research challenge. Here, we report a novel interconnected Si hollow nanosphere electrode that is capable of accommodating large volume changes without pulverization during cycling. We achieved the high initial discharge capacity of 2725 mAh g(-1) with less than 8% capacity degradation every hundred cycles for 700 total cycles. Si hollow sphere electrodes also show a Coulombic efficiency of 99.5% in later cycles. Superior rate capability is demonstrated and attributed to fast lithium diffusion in the interconnected Si hollow structure.
硅因其高理论比容量而成为锂离子电池阳极材料的有前途的候选者。然而，循环过程中的体积变化会导致粉碎和容量衰减，提高循环寿命是一个主要的研究挑战。在这里，我们报告了一种新型的互联 Si 空心纳米球电极，它能够在循环过程中不粉碎而适应大的体积变化。我们实现了 2725 mAh g(-1) 的高初始放电容量，在 700 次总循环中每 100 次循环的容量衰减小于 8%。Si 空心球电极在后期循环中也表现出 99.5%的库仑效率。优异的倍率性能归因于在互联 Si 空心结构中快速的锂离子扩散。
