A Comparative First-Principles Study on Sodiation of Silicon, Germanium, and Tin for Sodium-Ion Batteries
A Comparative First-Principles Study on Sodiation of Silicon, Germanium, and Tin for Sodium-Ion Batteries
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DOI：
10.1021/acs.jpcc.5b01099
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发表时间：
2015-07-09
影响因子：
3.7
通讯作者：
Hwang, Gyeong S.
中科院分区：
文献类型：
--
作者：
Chou, Chia-Yun;Lee, Myungsuk;Hwang, Gyeong S.
钠离子电池（NIB）作为现有锂离子电池（LIB）技术的潜在补充最近受到极大关注。由于Na和Li在性质上的差异，对于LIB来说有吸引力的阳极材料可以用于或可以不用于NIB。使用密度泛函理论计算，我们检查和比较的钠化行为的Si，Ge和Sn，在比较中，如果需要的话，他们的锂化过程。我们评估单钠纳入主机矩阵（M = Si，Ge，Sn），并讨论了形成的Na M合金的结构演变和能量，沿着与他们的机械和扩散性能。虽然在这项工作中考虑的合金系统似乎在钠化和锂化过程中经历了类似的转变，但在前者中，M网络往往更快地失去连通性。当Na/Li：M = 1：1时，a-NaM合金中的M网络已经分解成紧密的孤立团簇，而a-LiM合金中的M网络仍然通过褶皱构象保持延伸的连接性。与锂化的情况相比，它们的特定原子排列的这种独特差异有助于钠化的更快软化、更大的体积膨胀和Na扩散率的更快增加。
Sodium-ion batteries (NIBs) have recently received great attention as a potential complement to existing lithium-ion battery (LIB) technology. Because of the difference between Na and Li in nature, what has been an attractive anode material for LIBs may or may not be utilized for NIBs. Using density functional theory calculations, we examine and compare the sodiation behaviors of Si, Ge, and Sn, in comparison also to their lithiation processes if needed. We evaluate single Na incorporation in the host matrices (M = Si, Ge, Sn) and also discuss the formation of Na M alloys in terms of structural evolution and energetics, along with their mechanical and diffusion properties. While the alloy systems considered in this work appear to undergo similar transformation during sodiation and lithiation, the M networks tend to lose connectivity more rapidly in the former. At Na/Li:M = 1:1 ratio, the M networks in a-NaM alloys already disintegrate into compact isolated clusters while those in a-LiM still maintain extended connectivity via puckered conformation. This unique difference in their specific atomic arrangements contributes to the more rapid softening, larger volume expansion, and faster increase in Na diffusivity with sodiation in comparison to the case of lithiation.