Si/Ge Double-Layered Nanotube Array as a Lithium Ion Battery Anode

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• 作者：Taeseup Song ; Huanyu Cheng ; Heechae Choi ; Jin-Hyon Lee ; Hyungkyu Han ; Dong Hyun Lee ; Dong Su Yoo ; Moon-Seok Kwon ; Jae-Man Choi ; Seok Gwang Doo ; Hyuk Chang ; Jianliang Xiao ; Yonggang Huang ; Won Il Park ; Yong-Chae Chung ; Hansu Kim ; John A. Rogers ; Ungyu Paik
• 刊名：ACS Nano
• 出版年：2012
• 出版时间：January 24, 2012
• 年：2012
• 卷：6
• 期：1
• 页码：303-309
• 全文大小：501K
• 年卷期：v.6,no.1(January 24, 2012)
• ISSN：1936-086X

文摘

Problems related to tremendous volume changes associated with cycling and the low electron conductivity and ion diffusivity of Si represent major obstacles to its use in high-capacity anodes for lithium ion batteries. We have developed a group IVA based nanotube heterostructure array, consisting of a high-capacity Si inner layer and a highly conductive Ge outer layer, to yield both favorable mechanics and kinetics in battery applications. This type of Si/Ge double-layered nanotube array electrode exhibits improved electrochemical performances over the analogous homogeneous Si system, including stable capacity retention (85% after 50 cycles) and doubled capacity at a 3C rate. These results stem from reduced maximum hoop strain in the nanotubes, supported by theoretical mechanics modeling, and lowered activation energy barrier for Li diffusion. This electrode technology creates opportunities in the development of group IVA nanotube heterostructures for next generation lithium ion batteries.

Keywords:

silicon; germanium; nanotubes; anode; lithium ion batteries