Flexible energy storage devices based on nanocomposite paper

doi:10.1073/pnas.0706508104

Flexible energy storage devices based on nanocomposite paper

Departments of *Materials Science and Engineering and
^†Chemical and Biological Engineering, and Center for Biotechnology and Interdisciplinary Studies,
^‡Rensselaer Nanotechnology Center; Rensselaer Polytechnic Institute, Troy, NY 12180

Communicated by Mildred S. Dresselhaus, Massachusetts Institute of Technology, Cambridge, MA, July 11, 2007 (received for review February 23, 2007)

Abstract

There is strong recent interest in ultrathin, flexible, safe energy storage devices to meet the various design and power needs of modern gadgets. To build such fully flexible and robust electrochemical devices, multiple components with specific electrochemical and interfacial properties need to be integrated into single units. Here we show that these basic components, the electrode, separator, and electrolyte, can all be integrated into single contiguous nanocomposite units that can serve as building blocks for a variety of thin mechanically flexible energy storage devices. Nanoporous cellulose paper embedded with aligned carbon nanotube electrode and electrolyte constitutes the basic unit. The units are used to build various flexible supercapacitor, battery, hybrid, and dual-storage battery-in-supercapacitor devices. The thin freestanding nanocomposite paper devices offer complete mechanical flexibility during operation. The supercapacitors operate with electrolytes including aqueous solvents, room temperature ionic liquids, and bioelectrolytes and over record temperature ranges. These easy-to-assemble integrated nanocomposite energy-storage systems could provide unprecedented design ingenuity for a variety of devices operating over a wide range of temperature and environmental conditions.

Footnotes

^§To whom correspondence should be addressed. E-mail: ajayan{at}rpi.edu
Author contributions: V.L.P., M.M.S., A.K., R.J.L., O.N., and P.M.A. designed research; V.L.P., M.M.S., A.K., and S.M. performed research; V.L.P., A.K., S.M., L.C., and R.V. contributed new reagents/analytic tools; V.L.P., M.M.S., R.J.L., O.N., and P.M.A. analyzed data; and V.L.P., M.M.S., and P.M.A. wrote the paper.
The authors declare no conflict of interest.
This article contains supporting information online at www.pnas.org/cgi/content/full/0706508104/DC1.
Abbreviations:

CNT,

carbon nanotube;

[bmIm][Cl],

1-butyl,3-methylimidazolium chloride;

MWNT,

multiwalled nanotubes;

RTIL,

room temperature ionic liquid.