Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States.
Nano Lett. 2015 Jan 14;15(1):703-8. doi: 10.1021/nl504242k. Epub 2014 Dec 19.
Silicon can store Li(+) at a capacity 10 times that of graphite anodes. However, to harness this remarkable potential for electrical energy storage, one has to address the multifaceted challenge of volume change inherent to high capacity electrode materials. Here, we show that, solely by chemical tailoring of Si-carbon interface with atomic oxygen, the cycle life of Si/carbon matrix-composite electrodes can be substantially improved, by 300%, even at high mass loadings. The interface tailored electrodes simultaneously attain high areal capacity (3.86 mAh/cm(2)), high specific capacity (922 mAh/g based on the mass of the entire electrode), and excellent cyclability (80% retention of capacity after 160 cycles), which are among the highest reported. Even at a high rate of 1C, the areal capacity approaches 1.61 mAh/cm(2) at the 500th cycle. This remarkable electrochemical performance is directly correlated with significantly improved structural and electrical interconnections throughout the entire electrode due to chemical tailoring of the Si-carbon interface with atomic oxygen. Our results demonstrate that interfacial bonding, a new dimension that has yet to be explored, can play an unexpectedly important role in addressing the multifaceted challenge of Si anodes.
硅可以存储的锂离子是石墨阳极的 10 倍。然而，要利用这种高容量电极材料固有的体积变化的多方面挑战来实现储能的显著潜力，就必须解决问题。在这里，我们展示了，仅仅通过化学修饰硅-碳界面与原子氧，硅/碳基质复合材料电极的循环寿命可以得到极大的提高，高达 300%，即使在高质量负载下也是如此。经过界面修饰的电极同时具有高面容量（3.86 mAh/cm²）、高比容量（基于整个电极的质量为 922 mAh/g）和出色的循环稳定性（160 次循环后容量保持率为 80%），这是目前报道的最高值之一。即使在 1C 的高倍率下，在第 500 次循环时，面容量也接近 1.61 mAh/cm²。这种显著的电化学性能与由于原子氧化学修饰硅-碳界面而在整个电极中显著改善的结构和电连接直接相关。我们的结果表明，界面键合，一个尚未被探索的新维度，可以在解决硅阳极的多方面挑战方面发挥意想不到的重要作用。
