Minimized lithium trapping by isovalent isomorphism for high initial Coulombic efficiency of silicon anodes

Silicon demonstrates great potential as a next-generation lithium ion battery anode because of high capacity and elemental abundance. However, the issue of low initial Coulombic efficiency needs to be addressed to enable large-scale applications. There are mainly two mechanisms for this lithium loss...

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Bibliographic Details
Published in:Science advances 2019-11, Vol.5 (11), p.eaax0651-eaax0651
Main Authors: Zhu, Bin, Liu, Guoliang, Lv, Guangxin, Mu, Yu, Zhao, Yunlei, Wang, Yuxi, Li, Xiuqiang, Yao, Pengcheng, Deng, Yu, Cui, Yi, Zhu, Jia
Format: Article
Language:English
Subjects:
Applied Sciences and Engineering
ENERGY STORAGE
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Summary:Silicon demonstrates great potential as a next-generation lithium ion battery anode because of high capacity and elemental abundance. However, the issue of low initial Coulombic efficiency needs to be addressed to enable large-scale applications. There are mainly two mechanisms for this lithium loss in the first cycle: the formation of the solid electrolyte interphase and lithium trapping in the electrode. The former has been heavily investigated while the latter has been largely neglected. Here, through both theoretical calculation and experimental study, we demonstrate that by introducing Ge substitution in Si with fine compositional control, the energy barrier of lithium diffusion will be greatly reduced because of the lattice expansion. This effect of isovalent isomorphism significantly reduces the Li trapping by ~70% and improves the initial Coulombic efficiency to over 90%. We expect that various systems of battery materials can benefit from this mechanism for fine-tuning their electrochemical behaviors.
ISSN:2375-2548
2375-2548
DOI:10.1126/sciadv.aax0651