1. Lithium-ion capacitors with 2D Nb2CTx (MXene) – carbon nanotube electrodes.
- Author
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Byeon, Ayeong, Glushenkov, Alexey M., Anasori, Babak, Urbankowski, Patrick, Li, Jingwen, Byles, Bryan W., Blake, Brian, Van Aken, Katherine L., Kota, Sankalp, Pomerantseva, Ekaterina, Lee, Jae W., Chen, Ying, and Gogotsi, Yury
- Subjects
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LITHIUM-ion batteries , *CARBON nanofibers , *CARBON electrodes , *ENERGY storage , *ENERGY density , *GRAPHITE - Abstract
There is a growing interest to hybrid energy storage devices, such as lithium-ion capacitors, in which battery-type electrodes are combined with capacitor-type ones. It is anticipated that the energy density (either gravimetric or volumetric) of lithium-ion capacitors is improved if pseudocapacitive or fast insertion materials are used instead of conventional activated carbon (AC) in the capacitor-type electrode. MXenes, a new family of two-dimensional transition metal carbides, demonstrate metallic conductivity and fast charge-discharge behavior that make them suitable for this application. In this study, we move beyond single electrodes, half-cell studies and demonstrate three types of hybrid cells using Nb 2 CT x –carbon nanotube (CNT) films. It is shown that lithiated graphite/Nb 2 CT x -CNT, Nb 2 CT x -CNT/LiFePO 4 and lithiated Nb 2 CT x -CNT/Nb 2 CT x -CNT cells are all able to operate within 3 V voltage windows and deliver capacities of 43, 24 and 36 mAh/g (per total weight of two electrodes), respectively. Moreover, the polarity of the electrodes can be reversed in the symmetric Nb 2 CT x -CNT cells from providing a positive potential between 0 and 3 V to a negative one from −3 to 0 V. It is shown that the volumetric energy density (50–70 Wh/L) of our first-generation devices with MXene electrodes exceeds that of a lithium titanate/AC capacitor. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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