Graphical Abstract

Novel inexpensive, light, flexible, and even rollup or wearable devices are required for multi-functional portable electronics and developing new versatile and flexible electrode materials as alternatives to the materials used in contemporary batteries and supercapacitors is a key challenge. Here, binder-free activated carbon (AC)/carbon nanotube (CNT) paper electrodes for use in advanced supercapacitors have been fabricated based on low-cost, industrial-grade aligned CNTs. By a two-step shearing strategy, aligned CNTs were dispersed into individual long CNTs, and then 90 wt%–99 wt% of AC powder was incorporated into the CNT pulp and the AC/CNT paper electrode was fabricated by deposition on a filter. The specific capacity, rate performance, and power density of the AC/CNT paper electrode were better than the corresponding values for an AC/acetylene black electrode. The capacity reached a maximum value of 267.6 F/g with a CNT loading of 5 wt%, and the energy density and power density were 22.5 W·h/kg and 7.3 kW/kg at a high current density of 20 A/g. The AC/CNT paper electrode also showed a good cycle performance, with 97.5% of the original capacity retained after 5000 cycles at a scan rate of 200 mV/s. This method affords not only a promising paper-like nanocomposite for use in low-cost and flexible supercapacitors, but also a general way of fabricating multi-functional paper-like CNT-based nanocomposites for use in devices such as flexible lithium ion batteries and solar cells.
Rogers, J. A. Toward paperlike displays. Science 2001, 291, 1502–1503.
Rogers, J. A.; Someya, T.; Huang, Y. G. Materials and mechanics for stretchable electronics. Science 2010, 327, 1603–1607.
Kaempgen, M.; Chan, C. K.; Ma, J.; Cui, Y.; Gruner, G. Printable thin film supercapacitors using single-walled carbon nanotubes. Nano Lett. 2009, 9, 1872–1876.
Hu, L. B.; Pasta, M.; La Mantia, F.; Cui, L. F.; Jeong, S.; Deshazer, H. D.; Choi, J. W.; Han, S. M.; Cui, Y. Stretchable, porous, and conductive energy textiles. Nano Lett. 2010, 10, 708–714.
Nishide, H.; Oyaizu, K. Toward flexible batteries. Science 2008, 319, 737–738.
Li, X.; Rong, J. P.; Wei, B. Q. Electrochemical behavior of single-walled carbon nanotube supercapacitors under compressive stress. ACS Nano 2010, 4, 6039–6049.
Bae, J.; Song, M. K.; Park, Y. J.; Kim, J. M.; Liu, M. L.; Wang, Z. L. Fiber supercapacitors made of nanowire-fiber hybrid structures for wearable/flexible energy storage. Angew. Chem. Int. Ed. 2011, 50, 1683–1687.
Chen, Y. S.; Xu, Y. F.; Zhao, K.; Wan, X. J.; Deng, J. C.; Yan, W. B. Towards flexible all-carbon electronics: Flexible organic field-effect transistors and inverter circuits using solution-processed all-graphene source/drain/gate electrodes. Nano Res. 2010, 3, 714–721.
Chen, C. M.; Yang, Q. H.; Yang, Y. G.; Lv, W.; Wen, Y. F.; Hou, P. X.; Wang, M. Z.; Cheng, H. M. Self-assembled free-standing graphite oxide membrane. Adv. Mater. 2009, 21, 3007–3011.
Yan, X. B.; Tai, Z. X.; Chen, J. T.; Xue, Q. J. Fabrication of carbon nanofiber–polyaniline composite flexible paper for supercapacitor. Nanoscale 2011, 3, 212–216.
Nyholm, L.; Nyström, G.; Mihranyan, A.; Strømme, M. Toward flexible polymer and paper-based energy storage devices. Adv. Mater. 2011, DOI: 10.1002/adma.201004134.
Snook, G. A.; Kao, P.; Best, A. S. Conducting-polymer-based supercapacitor devices and electrodes. J. Power Sources 2011, 196, 1–12.
Li, G. R.; Feng, Z. P.; Ou, Y. N.; Wu, D. C.; Fu, R. W.; Tong, Y. X. Mesoporous MnO2/carbon aerogel composites as promising electrode materials for high-performance supercapacitors. Langmuir 2010, 26, 2209–2213.
Yan, J.; Wei, T.; Shao, B.; Fan, Z. J.; Qian, W. Z.; Zhang, M. L.; Wei, F. Preparation of a graphene nanosheet/polyaniline composite with high specific capacitance. Carbon 2010, 48, 487–493.
Chen, P. C.; Chen, H. T.; Qiu, J.; Zhou, C. W. Inkjet printing of single-walled carbon nanotube/RuO2 nanowire supercapacitors on cloth fabrics and flexible substrates. Nano Res. 2010, 3, 594–603.
Wang, D. W.; Li, F.; Zhao, J. P.; Ren, W. C.; Chen, Z. G.; Tan, J.; Wu, Z. S.; Gentle, I.; Lu, G. Q.; Cheng, H. M. Fabrication of graphene/polyaniline composite paper via in situ anodic electropolymerization for high-performance flexible electrode. ACS Nano 2009, 3, 1745–1752.
Kang, Y. J.; Kim, B.; Chung, H.; Kim, W. Fabrication and characterization of flexible and high capacitance super-capacitors based on MnO2/CNT/papers. Synth. Met. 2011, 160, 2510–2514.
Izadi-Najafabadi, A.; Yasuda, S.; Kobashi, K.; Yamada, T.; Futaba, D. N.; Hatori, H.; Yumura, M.; Iijima, S.; Hata, K. Extracting the full potential of single-walled carbon nanotubes as durable supercapacitor electrodes operable at 4 V with high power and energy density. Adv. Mater. 2010, 22, E235–E241.
Niu, Z. Q.; Zhou, W. Y.; Chen, J.; Feng, G. X.; Li, H.; Ma, W. J.; Li, J. Z.; Dong, H. B.; Ren, Y.; Zhao, D.; Xie, S. S. Compact-designed supercapacitors using free-standing single-walled carbon nanotube films. Energy Environ. Sci. 2011, 4, 1440–1446.
Zhang, L. L.; Zhao, X. S. Carbon-based materials as supercapacitor electrodes. Chem. Soc. Rev. 2009, 38, 2520–2531.
Frackowiak, E.; Beguin, F. Carbon materials for the electro-chemical storage of energy in capacitors. Carbon 2001, 39, 937–950.
Liu, C. G.; Yu, Z. N.; Neff, D.; Zhamu, A.; Jang, B. Z. Graphene-based supercapacitor with an ultrahigh energy density. Nano Lett. 2010, 10, 4863–4868.
Zhang, L. L.; Zhou, R.; Zhao, X. S. Graphene-based materials as supercapacitor electrodes. J. Mater. Chem. 2010, 20, 5983–5992.
Zhao, X. C.; Wang, A. Q.; Yan, J. W.; Sun, G. Q.; Sun, L. X.; Zhang, T. Synthesis and electrochemical performance of heteroatom-incorporated ordered mesoporous carbons. Chem. Mater. 2010, 22, 5463–5473.
Yang, X. Q.; Wu, D. C.; Chen, X. M.; Fu, R. W. Nitrogen-enriched nanocarbons with a 3-D continuous mesopore structure from polyacrylonitrile for supercapacitor application. J. Phys. Chem. C 2010, 114, 8581–8586.
Wu, D. C.; Chen, X.; Lu, S. H.; Liang, Y. R.; Xu, F.; Fu, R. W. Study on synergistic effect of ordered mesoporous carbon and carbon aerogel during electrochemical charge-discharge process. Micropor. Mesopor. Mater. 2010, 131, 261–264.
Wang, D. W.; Li, F.; Liu, M.; Lu, G. Q.; Cheng, H. M. 3D aperiodic hierarchical porous graphitic carbon material for high-rate electrochemical capacitive energy storage. Angew. Chem. Int. Ed. 2008, 47, 373–376.
Chmiola, J.; Largeot, C.; Taberna, P. L.; Simon, P.; Gogotsi, Y. Monolithic carbide-derived carbon films for micro-supercapacitors. Science 2010, 328, 480–483.
Fan, Z. J.; Yan, J.; Zhi, L. J.; Zhang, Q.; Wei, T.; Feng, J.; Zhang, M. L.; Qian, W. Z.; Wei, F. A three-dimensional carbon nanotube/graphene sandwich and its application as electrode in supercapacitors. Adv. Mater. 2010, 22, 3723–3728.
Beguin, F.; Szostak, K.; Lota, G.; Frackowiak, E. A self-supporting electrode for supercapacitors prepared by one-step pyrolysis of carbon nanotube/polyacrylonitrile blends. Adv. Mater. 2005, 17, 2380–2384.
Su, D. S.; Schlogl, R. Nanostructured carbon and carbon nano-composites for electrochemical energy storage applications. ChemSusChem 2010, 3, 136–168.
Yuan, C. Z.; Gao, B.; Shen, L. F.; Yang, S. D.; Hao, L.; Lu, X. J.; Zhang, F.; Zhang, L. J.; Zhang, X. G. Hierarchically structured carbon-based composites: Design, synthesis and their application in electrochemical capacitors. Nanoscale 2011, 3, 529–545.
Zhang, H.; Cao, G. P.; Wang, Z. Y.; Yang, Y. S.; Shi, Z. J.; Gu, Z. N. Growth of manganese oxide nanoflowers on vertically-aligned carbon nanotube arrays for high-rate electrochemical capacitive energy storage. Nano Lett. 2008, 8, 2664–2668.
Zhang, H.; Cao, G. P.; Wang, W. K.; Yuan, K. G.; Xu, B.; Zhang, W. F.; Cheng, J.; Yang, Y. S. Influence of micros-tructure on the capacitive performance of polyaniline/carbon nanotube array composite electrodes. Electrochim. Acta 2009, 54, 1153–1159.
Yan, J.; Fan, Z. J.; Wei, T.; Qian, W. Z.; Zhang, M. L.; Wei, F. Fast and reversible surface redox reaction of graphene–MnO2 composites as supercapacitor electrodes. Carbon 2010, 48, 3825–3833.
Meng, C. Z.; Liu, C. H.; Chen, L. Z.; Hu, C. H.; Fan, S. S. Highly flexible and all-solid-state paper like polymer super-capacitors. Nano Lett. 2010, 10, 4025–4031.
Meng, C. Z.; Liu, C. H.; Fan, S. S. Flexible carbon nanotube/polyaniline paper-like films and their enhanced electrochemical properties. Electrochem. Commun. 2009, 11, 186–189.
Yan, X. B.; Chen, J. T.; Yang, J.; Xue, Q. J.; Miele, P. Fabrication of free-standing, electrochemically active, and biocompatible graphene oxide–polyaniline and graphene–polyaniline hybrid papers. ACS Appl. Mater. Interf. 2010, 2, 2521–2529.
Zhang, X. J.; Shi, W. H.; Zhu, J. X.; Kharistal, D. J.; Zhao, W. Y.; Lalia, B. S.; Hng, H. H.; Yan, Q. Y. High-power and high-energy-density flexible pseudocapacitor electrodes made from porous CuO nanobelts and single-walled carbon nanotubes. ACS Nano 2011, 5, 2013–2019.
Lima, M. D.; Fang, S. L.; Lepro, X.; Lewis, C.; Ovalle-Robles, R.; Carretero-Gonzalez, J.; Castillo-Martinez, E.; Kozlov, M. E.; Oh, J. Y.; Rawat, N., Haines, C. S.; Haque, M. H.; Are, V.; Stoughton, S.; Zakhidov, A. A.; Baughman, R. H. Biscrolling nanotube sheets and functional guests into yarns. Science 2011, 331, 51–55.
Pico, F.; Pecharroman, C.; Anson, A.; Martinez, M. T.; Rojo, J. M. Understanding carbon–carbon composites as electrodes of supercapacitors—A study by AC and DC measurements. J. Electrochem. Soc. 2007, 154, A579–A586.
Taberna, P. L.; Chevallier, G.; Simon, P.; Plee, D.; Aubert, T. Activated carbon–carbon nanotube composite porous film for supercapacitor applications. Mater. Res. Bull. 2006, 41, 478–484.
Raymundo-Piñero, E.; Cadek, M.; Wachtler, M.; Béguin, F. Carbon nanotubes as nanotexturing agents for high power supercapacitors based on seaweed carbons. ChemSusChem DOI:10.1002/cssc.201000376.
Portet, C.; Taberna, P. L.; Simon, P.; Flahaut, E. Influence of carbon nanotubes addition on carbon–carbon supercapacitor performances in organic electrolyte. J. Power Sources 2005, 139, 371–378.
Xu, G. H.; Zhang, Q.; Huang, J. Q.; Zhao, M. Q.; Zhou, W. P.; Wei, F. A two-step shearing strategy to disperse long carbon nanotubes from vertically aligned multiwalled carbon nanotube arrays for transparent conductive films. Langmuir 2010, 26, 2798–2804.
Xu, G. H.; Zhang, Q.; Zhou, W. P.; Huang, J. Q.; Wei, F. The feasibility of producing MWCNT paper and strong MWCNT film from VACNT array. Appl. Phys. A 2008, 92, 531–539.
Zhang, Q.; Huang, J. Q.; Zhao, M. Q.; Qian, W. Z.; Wang, Y.; Wei, F. Radial growth of vertically aligned carbon nanotube arrays from ethylene on ceramic spheres. Carbon 2008, 46, 1152–1158.
Zhang, Q.; Zhao, M. Q.; Liu, Y.; Cao, A. Y.; Qian, W. Z.; Lu, Y. F.; Wei, F. Energy-absorbing hybrid composites based on alternate carbon-nanotube and inorganic layers. Adv. Mater. 2009, 21, 2876–2880.
Zhang, Q.; Zhao, M. Q.; Huang, J. Q.; Nie, J. Q.; Wei, F. Mass production of aligned carbon nanotube arrays by fluidized bed catalytic chemical vapor deposition. Carbon 2010, 48, 1196–1209.
Zhang, Q.; Zhao, M. Q.; Huang, J. Q.; Liu, Y.; Wang, Y.; Qian, W. Z.; Wei, F. Vertically aligned carbon nanotube arrays grown on a lamellar catalyst by fluidized bed catalytic chemical vapor deposition. Carbon 2009, 47, 2600–2610.
Bauhofer, W.; Kovacs, J. Z. A review and analysis of electrical percolation in carbon nanotube polymer composites. Compos. Sci. Technol. 2009, 69, 1486–1498.
Bose, S.; Khare, R. A.; Moldenaers, P. Assessing the strengths and weaknesses of various types of pre-treatments of carbon nanotubes on the properties of polymer/carbon nanotubes composites: A critical review. Polymer 2010, 51, 975–993.
Whitby, R. L. D.; Fukuda, T.; Maekawa, T.; James, S. L.; Mikhalovsky, S. V. Geometric control and tuneable pore size distribution of buckypaper and buckydiscs. Carbon 2008, 46, 949–956.
Zhao, M. Q.; Zhang, Q.; Huang, J. Q.; Nie, J. Q.; Wei, F. Advanced materials from natural materials: Synthesis of aligned carbon nanotubes on wollastonites. ChemSusChem 2010, 3, 453–459.
Xu, F.; Cai, R. J.; Zeng, Q. C.; Zou, C.; Wu, D. C.; Li, F.; Lu, X. E.; Liang, Y. R.; Fu, R. W. Fast ion transport and high capacitance of polystyrene-based hierarchical porous carbon electrode material for supercapacitors. J. Mater. Chem. 2011, 121, 1970–1976.
Futaba, D. N.; Hata, K.; Yamada, T.; Hiraoka, T.; Hayamizu, Y.; Kakudate, Y.; Tanaike, O.; Hatori, H.; Yumura, M.; Iijima, S. Shape-engineerable and highly densely packed single-walled carbon nanotubes and their application as super-capacitor electrodes. Nat. Mater. 2006, 5, 987–994.
Niu, C. M.; Sichel, E. K.; Hoch, R.; Moy, D.; Tennent, H. High power electrochemical capacitors based on carbon nanotube electrodes. Appl. Phys. Lett. 1997, 70, 1480–1482.
Du, C. S.; Pan, N. High power density supercapacitor electrodes of carbon nanotube films by electrophoretic deposition. Nanotechnology 2006, 17, 5314–5318.
Huang, C. W.; Hsu, C. H.; Kuo, P. L.; Hsieh, C. T.; Teng, H. S. Mesoporous carbon spheres grafted with carbon nanofibers for high-rate electric double layer capacitors. Carbon 2011, 49, 895–903.
Huang, C. W.; Chuang, C. M.; Ting, J. M.; Teng, H. S. Significantly enhanced charge conduction in electric double layer capacitors using carbon nanotube-grafted activated carbon electrodes. J. Power Sources 2008, 183, 406–410.