Arrays of Sealed Silicon Nanotubes As Anodes for Lithium Ion Batteries

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• 作者：Taeseup Song ; Jianliang Xia ; Jin-Hyon Lee ; Dong Hyun Lee ; Moon-Seok Kwon ; Jae-Man Choi ; Jian Wu ; Seok Kwang Doo ; Hyuk Chang ; Won Il Park ; Dong Sik Zang ; Hansu Kim ; Yonggang Huang ; Keh-Chih Hwang ; John
• 刊名：Nano Letters
• 出版年：2010
• 出版时间：May 12, 2010
• 年：2010
• 卷：10
• 期：5
• 页码：1710-1716
• 全文大小：549K
• 年卷期：v.10,no.5(May 12, 2010)
• ISSN：1530-6992

文摘

Silicon is a promising candidate for electrodes in lithium ion batteries due to its large theoretical energy density. Poor capacity retention, caused by pulverization of Si during cycling, frustrates its practical application. We have developed a nanostructured form of silicon, consisting of arrays of sealed, tubular geometries that is capable of accommodating large volume changes associated with lithiation in battery applications. Such electrodes exhibit high initial Coulombic efficiencies (i.e., >85%) and stable capacity-retention (>80% after 50 cycles), due to an unusual, underlying mechanics that is dominated by free surfaces. This physics is manifested by a strongly anisotropic expansion in which 400% volumetric increases are accomplished with only relatively small (<35%) changes in the axial dimension. These experimental results and associated theoretical mechanics models demonstrate the extent to which nanoscale engineering of electrode geometry can be used to advantage in the design of rechargeable batteries with highly reversible capacity and long-term cycle stability.