Electrochemical characterization of single-walled carbon nanotubes for electrochemical double layer capacitors using non-aqueous electrolyte

Ruch, Patrick; Kötz, R.; Wokaun, Alexander

doi:10.1016/j.electacta.2009.03.022

Cited by 80 publications

(61 citation statements)

References 41 publications

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“…Consequently, understanding the relationships between the electrochemical performance of supercapacitors and the structure of carbons may give additional information for optimizing these systems. For example, recent studies on SWCNT and ACs in organic electrolyte demonstrate clearly that the capacitance increase and resistance decrease under high polarization could be related to an electrochemical doping (shift of the Fermi level toward the valence band or the conduction band) of the graphene layers during charge, allowing the ''butterfly'' shape of voltamograms in the three-electrode cell to be partly explained [23,69]. As the electrochemical doping strongly depends on the structure of the carbon, this feature adds to the difficulty in interpreting the repartition of ions in micropores on charging the capacitor.…”

Section: Discussionmentioning

confidence: 99%

Electrical Double‐Layer Capacitors and Carbons for EDLCs

2013

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IntroductionAccumulators, electrochemical capacitors (ECs) (or supercapacitors), and capacitors are the three main electrochemical systems that can be used to store energy. As described in the so-called Ragone plot shown in Figure 4.1, each of these systems offers different characteristics in terms of specific power and energy. From a general point of view, accumulators, and more precisely Li-ion batteries, can store high energy densities (up to 180 Wh kg −1 for commercial products) with low-power densities (up to about 2 kW kg −1 ). Electrical double-layer capacitors (EDLCs) can deliver very high-power density (15 kW kg −1 ) with lower stored energy (5 Wh kg −1 ) than that of batteries.EDLCs can be applied in the case of stationary and mobile systems requiring highpower pulses: car acceleration, tramways, cranes, forklifts, emergency systems, and so on. Moreover, owing to their low time constant, they can quickly harvest energy, for example, during deceleration or braking of vehicles.Although EDLCs are able to provide high power with a long cycle life compared to accumulators, they suffer from a relatively low energy density. Therefore, the main ongoing research direction concerns the optimization of the existing electrode materials and the development of new materials.Industrial EDLCs are essentially based on nanoporous carbon electrodes. The reasons for this choice lie in the high availability, low cost, chemical inertness, and good electrical conductivity of activated carbons (ACs), as well as a high versatility of texture and surface functionality. For these reasons, this chapter presents the capacitance properties of carbon-based electrodes, showing optimization strategies playing on the structure/nanotexture of the carbon and on the nature of the electrolyte.

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Section: Discussionmentioning

confidence: 99%

Electrical Double‐Layer Capacitors and Carbons for EDLCs

2013

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“…15 A recent study on SWNTs in an organic electrolyte (1 M Et 4 NBF 4 /acetonitrile) has shown capacitance similar to commercial activated carbons. 16 Gravimetric capacitance has also been observed to vary in the range of 7 and 20 F/g for SWNTs as compared to 9-32 F/g for activated carbons. Though the inherent capacitance of carbon nanotubes is small, their high electronic conductivity, mechanical strength and unique three-dimensional morphology have made them very useful templates for high power applications wherein pseudocapacitor materials such as conducting polymers or metal oxides are deposited on the carbon nanotubes and the composite is used as electrode for supercapacitors.…”

Section: Advancing the Supercapacitor Materials And Technology Frontimentioning

confidence: 99%

Advancing the Supercapacitor Materials and Technology Frontier for Improving Power Quality

Jampani

Manivannan

Kumta

2010

Electrochem. Soc. Interface

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Electrochemical supercapacitors are emerging devices of prime importance in energy sustainability due to their superior characteristics, unmatched by any other charge storage device. These exceptional properties include: 1) high power densities at relatively high energy densities and 2) long cycle life. These characteristics have already been exploited in various applications such as power electronics, large scale transport systems comprising subway trains and buses, energy storage at intermittent generators including windmills, and smart grid applications. Smart grid needs will include grid stability, frequency smoothing, peak shifting, and frequency regulation. This interest has spurned a large number of interesting technologies including the evolution of new materials for use in the electrodes such as graphene, transition metal oxides, and transition metal nitrides. The use of non-aqueous electrolytes and ionic liquids has also led to very high energy densities. The challenge however, lies in maintaining cyclability and stability at high rates.

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“…At high frequencies, with the decrease of the frequency, Nyquist plot exhibits a ''Warburg like'' behaviour, which illustrates the expected shape for double layer charging of porous electrodes, consisting of a high frequency region with a slope of about 45 and a low frequency region in which an capacitive behavior is approached. 22,38 In Fig. 6a, it can be seen that the knee frequency is about 17 Hz, indicating the availability of the rolled design of SWCNT film supercapacitor.…”

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confidence: 99%

“…Besides, postdeposited SWCNT film on the substrates can be used as electrode materials for the supercapacitor and excellent results have been reported. [21][22][23][24] However, these SWCNT films used as supercapacitor electrodes have to be deposited onto the substrates and the resulting SWCNT films with substrates are not flexible and tough enough. SWCNT arrays were also used as the electrodes of supercapacitors and ultrahigh energy density and power density were achieved.…”

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Compact-designed supercapacitors using free-standing single-walled carbon nanotube films

Niu

Zhou

Chen

et al. 2011

Energy Environ. Sci.

321

214

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We reported the realization of assembling compact-designed supercapacitors using large-scaled freestanding and flexible single-walled carbon nanotube (SWCNT) films as both anode and cathode. A prototype of the processing procedures was developed to obtain the uniform spreading of the SWCNT films onto the separators serving as both electrodes and charge collectors without metallic current collectors, leading to a simplified and lightweight architecture. The area of SWCNT film on a separator can be scaled up and its thickness can be extended. High energy and power densities (43.7 Wh kg -1 and 197.3 kW kg -1 , respectively) were achieved from the prepared SWCNT film-based compact-designed supercapacitors with small equivalent series resistance. The specific capacitance of this kind of compact-designed SWCNT film supercapacitor is about 35 F g -1 . These results clearly show the potential application of free-standing SWCNT film in compact-designed supercapacitor with enhanced performance and significantly improved energy and power densities. We reported the realization of assembling compact-designed supercapacitors using large-scaled freestanding and flexible single-walled carbon nanotube (SWCNT) films as both anode and cathode. A prototype of the processing procedures was developed to obtain the uniform spreading of the SWCNT films onto the separators serving as both electrodes and charge collectors without metallic current collectors, leading to a simplified and lightweight architecture. The area of SWCNT film on a separator can be scaled up and its thickness can be extended. High energy and power densities (43.7 Wh kg À1 and 197.3 kW kg À1, respectively) were achieved from the prepared SWCNT film-based compact-designed supercapacitors with small equivalent series resistance. The specific capacitance of this kind of compact-designed SWCNT film supercapacitor is about 35 F g À1 . These results clearly show the potential application of free-standing SWCNT film in compact-designed supercapacitor with enhanced performance and significantly improved energy and power densities.

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Electrochemical characterization of single-walled carbon nanotubes for electrochemical double layer capacitors using non-aqueous electrolyte

Cited by 80 publications

References 41 publications

Electrical Double‐Layer Capacitors and Carbons for EDLCs

Electrical Double‐Layer Capacitors and Carbons for EDLCs

Advancing the Supercapacitor Materials and Technology Frontier for Improving Power Quality

Compact-designed supercapacitors using free-standing single-walled carbon nanotube films

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