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Lithium-ion capacitors with 2D Nb2CTx (MXene) – carbon nanotube electrodes

journal contribution
posted on 15.09.2016, 00:00 authored by A Byeon, Alexey Glushenkov, B Anasori, P Urbankowski, J Li, B W Byles, B Blake, K L Van Aken, S Kota, E Pomerantseva, J W Lee, Ying (Ian) ChenYing (Ian) Chen, Y Gogotsi
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 Nb2CTx-carbon nanotube (CNT) films. It is shown that lithiated graphite/Nb2CTx-CNT, Nb2CTx-CNT/LiFePO4 and lithiated Nb2CTx-CNT/Nb2CTx-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 Nb2CTx-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.

History

Journal

Journal of power sources

Volume

326

Pagination

686 - 694

Publisher

Elsevier

Location

Amsterdam, The Netherlands

ISSN

0378-7753

Language

eng

Publication classification

C Journal article; C1 Refereed article in a scholarly journal

Copyright notice

2016, Elsevier B.V.