Center for Computational Materials, Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas 78712.
Nano Lett. 2010 Mar 10;10(3):821-5. doi: 10.1021/nl903183n.
The ability to control the diffusion of dopants or impurities is a controlling factor in the functionalization of materials used in devices both at the macro- and nanoscales. At the nanoscale, manipulating diffusion of dopants is complicated by a number of factors such as the role of quantum confinement and the large surface to volume ratio. Here we examine Li in Si nanostructures, as atoms with low atomic mass such as Li can be used as a carrier for energy storage with high specific energy capacity. Specifically, Li-ion batteries with specific energy capacity as high as 4200 mA h g(-1) using Si nanowires as anodes have been achieved. Using ab initio calculations, we determine how the factors of size and dimensionality can be used to achieve an optimal diffusion of Li atoms in Si nanostructures.
控制掺杂剂或杂质扩散的能力是在宏观和纳米尺度上用于器件的材料功能化的控制因素。在纳米尺度上，掺杂剂的扩散受到多种因素的影响，例如量子限制和大的表面积与体积比的作用。在这里，我们研究了硅纳米结构中的 Li，因为低原子质量的原子（如 Li）可用作具有高比能量容量的能量存储的载体。具体而言，使用硅纳米线作为阳极，已经实现了比能量容量高达 4200 mA h g(-1)的锂离子电池。使用从头算计算，我们确定了尺寸和维度因素如何用于实现硅纳米结构中 Li 原子的最佳扩散。
