Electrochemical capacitors fabricated with carbon nanotubes grown within the pores of anodized aluminum oxide templates

Ahn, Hyo Jun; Sohn, Jung Inn; Kim, Youn Su; Shim, Hee Sang; Kim, Won; Seong, Tae Yeon

doi:10.1016/j.elecom.2006.01.018

Cited by 48 publications

(14 citation statements)

References 18 publications

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“…As shown in Fig. 3C, the specific capacitances of all-paper SCs at various currents are superior to the previously reported values with pure CNT electrodes on flat substrates (6,(26)(27)(28)(29)(30)(31)(32)(33), and are even close to those of pseudocapacitors based on the polymer/CNT composites (34,35). A high specific capacitance of 200 F/g was achieved for devices in sulfuric acid electrolyte (Fig.…”

Section: Resultssupporting

confidence: 66%

See 1 more Smart Citation

Highly conductive paper for energy-storage devices

Hu¹,

Choi²,

Yang³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

1,150

899

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Paper, invented more than 2,000 years ago and widely used today in our everyday lives, is explored in this study as a platform for energy-storage devices by integration with 1D nanomaterials. Here, we show that commercially available paper can be made highly conductive with a sheet resistance as low as 1 ohm per square (⍀/sq) by using simple solution processes to achieve conformal coating of single-walled carbon nanotube (CNT) and silver nanowire films. Compared with plastics, paper substrates can dramatically improve film adhesion, greatly simplify the coating process, and significantly lower the cost. Supercapacitors based on CNT-conductive paper show excellent performance. When only CNT mass is considered, a specific capacitance of 200 F/g, a specific energy of 30 -47 Watt-hour/kilogram (Wh/kg), a specific power of 200,000 W/kg, and a stable cycling life over 40,000 cycles are achieved. These values are much better than those of devices on other flat substrates, such as plastics. Even in a case in which the weight of all of the dead components is considered, a specific energy of 7.5 Wh/kg is achieved. In addition, this conductive paper can be used as an excellent lightweight current collector in lithiumion batteries to replace the existing metallic counterparts. This work suggests that our conductive paper can be a highly scalable and low-cost solution for high-performance energy storage devices.conformal coating ͉ carbon nanotubes ͉ nanomaterial ͉ solution process P rintable solution processing has been exploited to deposit various nanomaterials, such as fullerene, carbon nanotubes (CNTs), nanocrystals, and nanowires for large-scale applications, including thin-film transistors (1-3), solar cells (4, 5), and energy-storage devices (6, 7), because the process is low-cost while maintaining the unique properties of the nanomaterials. In these processes, flat substrates, such as glass, metallic films, Si wafers, and plastics, have been used to hold nanostructure films. Nanostructured materials are usually first capped with surfactant molecules so that they can be well-dispersed as separated particles in a solvent to form ''ink.'' The ink is then deposited onto the flat substrates, followed by surfactant removal and solvent evaporation. To produce high-quality films, significant efforts have been spent on ink formulation and rheology adjustment. Moreover, because the surfactants are normally insulating, and thus limit the charge transfer between the nanomaterials, their removal is particularly critical. However, this step involves extensive washing and chemical displacement, which often cause mechanical detachment of the film from the flat substrate. Polymer binders or adhesives have been used to improve the binding of nanomaterials to substrates, but these can also cause an undesirable decrease in the film conductivity. These additional procedures increase the complexity of solution processing and result in high cost and low throughput. Here, we exploit paper substrates used in daily life to solve these issues a...

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Section: Resultssupporting

confidence: 66%

“…CNTs deposited on porous paper are more accessible to ions in the electrolyte than those on flat substrates (6,(26)(27)(28)(29)(30)(31)(32)(33), which can result in high power density. In addition, the paper itself can function well as a separator.…”

Section: Resultsmentioning

confidence: 99%

Highly conductive paper for energy-storage devices

Hu¹,

Choi²,

Yang³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

1,150

899

View full text Add to dashboard Cite

show abstract

“…[236,237] The capacitance of smaller diameter CNTsi su sually higher than that of larger ones, which is due to the higher specific surface area in the network of smaller CNTs. [238] The low resistance of CNT electrodes ensures the high power of ECs. To reduce the contact resistance, CNTsc an be grown directly on current collectors such as graphite [239] and Inconel alloy.…”

Section: Carbonnanotubes For Ecsmentioning

confidence: 99%

Carbon‐Based Materials for Lithium‐Ion Batteries, Electrochemical Capacitors, and Their Hybrid Devices

2015

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A rapidly developing market for portable electronic devices and hybrid electrical vehicles requires an urgent supply of mature energy-storage systems. As a result, lithium-ion batteries and electrochemical capacitors have lately attracted broad attention. Nevertheless, it is well known that both devices have their own drawbacks. With the fast development of nanoscience and nanotechnology, various structures and materials have been proposed to overcome the deficiencies of both devices to improve their electrochemical performance further. In this Review, electrochemical storage mechanisms based on carbon materials for both lithium-ion batteries and electrochemical capacitors are introduced. Non-faradic processes (electric double-layer capacitance) and faradic reactions (pseudocapacitance and intercalation) are generally explained. Electrochemical performance based on different types of electrolytes is briefly reviewed. Furthermore, impedance behavior based on Nyquist plots is discussed. We demonstrate the influence of cell conductivity, electrode/electrolyte interface, and ion diffusion on impedance performance. We illustrate that relaxation time, which is closely related to ion diffusion, can be extracted from Nyquist plots and compared between lithium-ion batteries and electrochemical capacitors. Finally, recent progress in the design of anodes for lithium-ion batteries, electrochemical capacitors, and their hybrid devices based on carbonaceous materials are reviewed. Challenges and future perspectives are further discussed.

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“…Carbon nanotubes (CNTs) have attracted much attention as a good candidate as the electrodes in ESs, due to their chemical stability, high conductivity, large specific surface area, etc. [3][4][5]. To further improve capacitive performance of ESs, the metal oxide, such as RuO 2 , NiO x , and IrO 2 , have been introduced into CNT electrodes [6].…”

Section: Introductionmentioning

confidence: 99%