Arrays of Sealed Silicon Nanotubes As Anodes for Lithium Ion Batteries
Arrays of Sealed Silicon Nanotubes As Anodes for Lithium Ion Batteries
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DOI：
10.1021/nl100086e
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发表时间：
2010-05-01
期刊：
影响因子：
10.8
通讯作者：
Paik, Ungyu
中科院分区：
文献类型：
--
作者：
Song, Taeseup;Xia, Jianliang;Paik, Ungyu
硅由于其大的理论能量密度而成为锂离子电池中电极的有希望的候选者。由于硅在循环过程中的粉化，导致其容量保持性差，阻碍了其实际应用。我们开发了一种纳米结构形式的硅，由密封的管状几何形状阵列组成，能够适应电池应用中与锂化相关的大体积变化。这种电极表现出高的初始库仑效率（即，>85%）和稳定的容量保持率（50次循环后>80%），这是由于自由表面占主导地位的不寻常的基础力学。这种物理现象表现为强烈的各向异性膨胀，其中400%的体积增加仅用相对较小的（
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 (