Ultrafast Solvent-Assisted Sodium Ion Intercalation into Highly Crystalline Few-Layered Graphene
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- 作者：Adam P. Cohn ; Keith Share ; Rachel Carter ; Landon Oakes ; Cary L. Pint
- 刊名：Nano Letters
- 出版年：2016
- 出版时间：January 13, 2016
- 年：2016
- 卷：16
- 期：1
- 页码：543-548
- 全文大小：469K
- ISSN：1530-6992
文摘
A maximum sodium capacity of ～35 mAh/g has hampered the use of crystalline carbon nanostructures for sodium ion battery anodes. We demonstrate that a diglyme solvent shell encapsulating a sodium ion acts as a “nonstick” coating to facilitate rapid ion insertion into crystalline few-layer graphene and bypass slow desolvation kinetics. This yields storage capacities above 150 mAh/g, cycling performance with negligible capacity fade over 8000 cycles, and ～100 mAh/g capacities maintained at currents of 30 A/g (～12 s charge). Raman spectroscopy elucidates the ordered, but nondestructive cointercalation mechanism that differs from desolvated ion intercalation processes. In situ Raman measurements identify the Na+ staging sequence and isolates Fermi energies for the first and second stage ternary intercalation compounds at ～0.8 eV and ～1.2 eV.