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Graphene-based materials as supercapacitor electrodes
X. S. Zhao
Abstract
Supercapacitors (also known as ultracapacitors or electrical double-layer capacitors) are energy storage devices with distinct features, such as high power density and long cyclibility. Supercapacitor technology stands as a bridge between the high-power output of conventional capacitors and the high-energy characteristics of batteries and fuel cells. Supercapacitors are extremely versatile as an energy supply for applications in which significant energy is needed in pulse form, such as in electrical and hybrid vehicles. Supercapacitors store energy using either ion adsorption (electrical double-layer capacitors) or fast and reversible faradic reactions (pseudocapacitors). These two mechanisms can function simultaneously depending on the nature of electrode materials. Electrode materials have been the key in the successful development of high-energy supercapacitors (see one of our recent review articles on supercapacitors1).
Graphene, one-atom-thick planar sheet of sp2-bonded carbon atoms densely packed in a honeycomb crystal lattice, has recently grabbed appreciable attention due to its exceptional properties, including chemical inertness, optical transmittance, high electronic and conductivity, excellent thermal/mechanical stability, and easy processibility (see recent review articles2-5). Such thin platelets that are colloidally stable can be used as the primary building blocks for fabricating various graphene structures and architectures. In this seminar talk, I will briefly describe our research program on advanced porous materials for emerging applications. Then, I will discuss our recent work on porous carbon-based materials as electrodes for high-energy, high-power, long cycle life supercapacitor applications, followed by presenting our very recent research results on graphene-conducting-polymer6,7 and graphene-carbon-nanotube8 composites with an extremely high energy density.
References
- Zhang L L and Zhao X S, Chem. Soc. Rev. 2009, 38: 2520-2531.
- Geim A K et al., Nat. Mater. 2007, 6: 183-191.
- Allen M J et al., Chem. Rev. 2010, 110: 132-145.
- Compton O C and Nguyen S T, Small, 2010, 6: 711-723.
- Choi W et al., Critical Rev. Solid State and Mater. Sci. 2010, 35: 52-71.
- Zhang L L et al., J. Mater. Chem. 2010, in press.
- Zhang K et al., Chem Mater. 2010, 22: 1392-1401.
- Zhang L L et al., unpublished results.
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