Realizing the Full Potential of Insertion Anodes for Mg-Ion Batteries Through the Nanostructuring of Sn

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• 作者：Lucas R. Parent ; Yingwen Cheng ; Peter V. Sushko ; Yuyan Shao ; Jun Liu ; Chong-Min Wang ; Nigel D. Browning
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：February 11, 2015
• 年：2015
• 卷：15
• 期：2
• 页码：1177-1182
• 全文大小：373K
• ISSN：1530-6992

文摘

Magnesium is of great interest as a replacement for lithium in next-generation ion-transfer batteries but Mg-metal anodes currently face critical challenges related to the formation of passivating layers during Mg-plating/stripping and anode鈥揺lectrolyte鈥揷athode incompatibilities.1鈭? Alternative anode materials have the potential to greatly extend the spectrum of suitable electrolyte chemistries2,7 but must be systematically tailored for effective Mg²⁺ storage. Using analytical (scanning) transmission electron microscopy ((S)TEM) and ab initio modeling, we have investigated Mg²⁺ insertion and extraction mechanisms and transformation processes in 尾-SnSb nanoparticles (NPs), a promising Mg-alloying anode material. During the first several charge鈥揹ischarge cycles (conditioning), the 尾-SnSb particles irreversibly transform into a porous network of pure-Sn and Sb-rich subparticles, as Mg ions replace Sn atoms in the SnSb lattice. After electrochemical conditioning, small Sn particles/grains (<33 卤 20 nm) exhibit highly reversible Mg-storage, while the Sb-rich domains suffer substantial Mg trapping and contribute little to the system performance. This result strongly indicates that pure Sn can act as a high-capacity Mg-insertion anode as theoretically predicted,8 but that its performance is strongly size-dependent, and stable nanoscale Sn morphologies (<40 nm) are needed for superior, reversible Mg-storage and fast system kinetics.