Self-standing positive electrodes of oxidized few-walled carbon nanotubes for light-weight and high-power lithium batteries

Lee, Seung Woo; Gallant, Betar M.; Lee, Young-Min; Yoshida, Noboru; Kim, Dong Young; Yamada, Yuki; Noda, Suguru; Yamada, Atsuo; Shao‐Horn, Yang

doi:10.1039/c1ee02409d

Cited by 132 publications

(124 citation statements)

References 27 publications

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“…At higher rates (>10 A/g), the gravimetric capacitance of LbL-MWNT electrodes in asymmetric Li cells dropped rapidly to below 50 F/g, supporting the fact that additional capacitance attainable from faradaic reactions at lower currents is not accessible at very high rates and that double-layer charging becomes dominant. Figure 6 additionally compares LbL-MWNT electrode capacitance with reported literature values in various carbon nanotube 17,33,42 -and graphene 4,18,43,44 -based electrodes in organic electrolytes. At intermediate gravimetric currents (1-100 A/g), LbL-MWNT electrodes in asymmetric Li cells exhibit comparable gravimetric capacitances compared to single-walled carbon nanotube (100 μm), 17 microwave exfoliated graphene oxide (40-50 μm), 44 CNT-coated papers (∼10 μm), 42 and mesoporous graphene 18 (thickness not specified).…”

Section: Influence Of the Electrolyte Salt On Faradaic Reactions In Lblmentioning

confidence: 94%

Electrochemical Performance of Thin-Film Functionalized Carbon Nanotube Electrodes in Nonaqueous Cells

Gallant

Lee

Kawaguchi

et al. 2014

J. Electrochem. Soc.

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Charge storage mechanisms in oxygen-functionalized, multiwall carbon nanotube (MWNT) electrodes fabricated by the Layerby-Layer (LbL) self-assembly process were studied in two-electrode nonaqueous cells. In asymmetric cells with a Li metal or a lithium titanate (Li 4 Ti 5 O 12 ) negative electrode, double-layer charging of MWNT surfaces is supplemented by surface faradaic reactions between Li + and oxygen functional groups. The utilization of faradaic reactions leads to high gravimetric energies of 350 Wh/kg electrode (with Li) and 140 Wh/kg electrode (with LTO) at 5 kW/kg electrode . Self-discharge studies of LbL-MWNT electrodes in asymmetric Li cells revealed that charge leakage comparable to traditional symmetric double-layer capacitors occurs at open circuit, and the presence of surface faradaic reactions accelerates the voltage recovery for electrodes polarized below open circuit voltage. Studies in different electrolytes reveal that both Li + and TEA + can participate in faradaic reactions with surface oxygen. The role of faradaic reactions is further demonstrated by tests in symmetric cells composed of two identical LbL-MWNT electrodes, where charge storage is limited to double layer charging owing to electrolyte charge neutrality requirements. As a result, the electrode energy decreased substantially (40 Wh/kg electrode at 5 kW/kg electrode ).Electrochemical capacitors (ECs) 1-8 play an important role as energy storage devices in applications requiring high power and durability, from rapid-charging power tools and load leveling of the electric grid 3,6,9 to integrated power supplies for on-chip and microscale devices. 7,10,11 ECs, which store charge by physical charge separation and/or surface faradaic reactions (pseudocapacitance) at the electrode surface, exhibit high cell gravimetric powers (10 kW/kg cell ) compared to Li-ion batteries (1 kW/kg cell ) 5 and can undergo hundreds of thousands of cycles with minimal capacity fade. 3 However, a major limitation of ECs is low gravimetric energy density (5 Wh/kg cell ) compared to Li-ion batteries (100 Wh/kg cell ), 5 where Li-ion batteries achieve higher energies through intercalation redox reactions utilizing the entire volume of storage materials. Thus, it is critical to develop electrode materials that can improve the energy density of high-power, long cycle life materials and devices by combining the charge storage elements of batteries and ECs.The gravimetric energy of an EC is proportional to the product of cell capacitance, C, and the square of the cell voltage, V, by E = 1 2 CV 2 . Strategies to increase the gravimetric energy of devices have focused on increasing both of these parameters. High capacitance is achieved using electrode materials with high specific surface areas such as nanoporous (e.g. activated) carbons (1000-2000 m 2 /g), 12 where gravimetric capacitances of 150-200 F/g carbon are commonly reported in aqueous cells. 2 In nonaqueous cells, fine-tuning of the pore size relative to the desolvated ion size 10,11,13,14 yields a severalfo...

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Section: Influence Of the Electrolyte Salt On Faradaic Reactions In Lblmentioning

confidence: 94%

Electrochemical Performance of Thin-Film Functionalized Carbon Nanotube Electrodes in Nonaqueous Cells

Gallant

Lee

Kawaguchi

et al. 2014

J. Electrochem. Soc.

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“…3D CNTs for SCs can be simply fabricated through self-assembly of functionalized MWNTs, using layer-by-layer (LBL) assembly [55] or vacuum-filtration. [144] In a typical LBL process (Figure 6), carboxylated MWNTs and amine-functionalized MWNTs were prepared and assembled onto ITO-coated glass slides alternately by adjusting the pH values of the solutions. [55] The obtained LBL-MWNT electrodes have a density of 0.83 g cm −3 , and show a much higher volumetric capacitance of ≈180 F cm −3 in non-aqueous electrolyte.…”

Section: D Cnt Hybrid Electrodesmentioning

confidence: 99%

Carbon Nanomaterials in Different Dimensions for Electrochemical Energy Storage

2016

Advanced Energy Materials

255

109

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In spite of an ongoing advancement, current popular EES systems including Li-ion batteries (LIBs), supercapacitors (SCs), and redox flow cells (RFCs) are limited by severe performance challenges of electrode materials in terms of low energy and power density as well as short durability. To mitigate the issues, carbon nanomaterials could be introduced to these EES systems, taking advantage of their unique geometry, excellent conductivity, large surface area, and intrinsic flexibility. Numerous carbon nanomaterial based EES systems, where carbon nanomaterials are adopted as either conducting additive or active electrode, have been developed and demonstrated appealing energy and power features. With the capability to enhance the structural and electrochemical properties of electrodes, carbon nanomaterials and their derivatives offer a wide range of possibilities to design advanced EES devices that can meet our growing energy and power demands in the future.A number of reviews have been published in the past few years on the application of carbon nanomaterials in EES. [5][6][7][8] However, this area is so active and new works accumulate very quickly. Therefore, it is helpful to update the new designs and outcomes. This progress report will summarize the most exciting recent (from the year 2010 onwards) advances in the application of carbon nanomaterials with different dimensions, i.e., 0D fullerene, 1D CNT, 2D graphene, and 3D assemblies of CNT and graphene, in EES systems, and highlight the new trends in the field. Besides the repetitively reviewed LIBs and SCs, this work will also deal with another important system, the RFC, which has been rejuvenated recently and is becoming increasingly vital for large scale energy storage. The recent EES applications of carbon nanomaterials will be discussed based on their dimensions. Structure and Properties of Various Nanostructured CarbonFullerenes, CNTs, and graphene all present conjugated π electron systems. The unique electronic configuration combined with geometric structure endows them with extraordinary properties, which make them superior to their competitors for specific applications such as EES. 0D FullerenesFullerene normally has a hollow sphere or ellipsoid shape. Specifically, C 60 has a cage-like fused-ring structure (truncated Carbon nanomaterials including fullerenes, carbon nanotubes, graphene, and their assemblies represent a unique type of materials in diverse formats and dimensions. They feature a large surface area, superior conductivity, fast charge transport, and intrinsic stability, which are essentially required for vari ous electrochemical energy storage (EES) systems such as Li-ion batteries, supercapacitors, and redox flow cells. The scaled-up and reliable production and assembly of carbon nanomaterials is a prerequisite for the development of carbon nanomaterial-based EES devices. In this progress report, the preparation of carbon nanostructures and the state-of-the-art applications of carbon nanomaterials with different dimensions in versatile EES...

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“…[31] The flexible CNT film formed by oxidized CNTs, which had abundant hydrophilic groups (carboxyl and hydroxyl), was able to show high capacitance even for Li ion intercalations in Li ion electrolyte. [32] Beside freestanding thick CNT film, vacuum filtration is also effective for the preparation of ultra-thin transparent CNT film, which can be subsequently transferred onto flexible and transparent polymer films for flexible/transparent supercapacitors. [33] Such CNT network film showed superior mechanical performance to brittle indium-tin oxide (ITO) film and large specific area for EDL capacitance, thus exhibited excellent electrochemical performance even under bending conditions.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and functionalization of carbon nanotube films for high-performance flexible supercapacitors

Chen

Zeng

Chen

et al. 2015

Carbon

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Self-standing positive electrodes of oxidized few-walled carbon nanotubes for light-weight and high-power lithium batteries

Cited by 132 publications

References 27 publications

Electrochemical Performance of Thin-Film Functionalized Carbon Nanotube Electrodes in Nonaqueous Cells

Electrochemical Performance of Thin-Film Functionalized Carbon Nanotube Electrodes in Nonaqueous Cells

Carbon Nanomaterials in Different Dimensions for Electrochemical Energy Storage

Fabrication and functionalization of carbon nanotube films for high-performance flexible supercapacitors

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