Carbon aerogel composite electrodes

Wang, Joseph.; Angnes, Lúcio; Tobias, Haim; Roesner, Rebecca A.; Hong, K.; Glass, Robert J.; Kong, Fung Ming.; Pekala, R.W.

doi:10.1021/ac00065a022

Cited by 69 publications

(35 citation statements)

References 3 publications

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“…This optimized nanotube network could then be backfilled with a host material. For example, we found that immersing the aerogel in a liquid led to complete impregnation of the aerogel through a "wicking" [20] or infiltration [21] process. The liquid could be a polymer or other material that could be subsequently cured to form a solid composite.…”

mentioning

confidence: 99%

Carbon Nanotube Aerogels

et al. 2007

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Aerogels are ultralight, highly porous materials typically fabricated by subjecting a wet-gel precursor to critical-pointdrying (CPD) or lyophilization (freeze-drying) in order to remove background liquid without collapsing the network. Microscopically, aerogels are composed of tenuous networks of clustered nanoparticles, and the materials often have unique properties, including very high strength-to-weight and surface-area-to-volume ratios. To date most aerogels are fabricated from silica [1] or pyrolized organic polymers. [2,3] Practical interest in the former stems from their potential for ultralight structural media, radiation detectors, and thermal insulators, [1] and in the latter from their potential for battery electrodes and supercapacitors. [2] In this paper we investigate the properties of a new class of aerogels based on carbon nanotubes (CNTs). Small-diameter CNTs, such as single-and few-wall CNTs, are exciting candidates for electrically conducting aerogels. Individually, these nanotubes are extraordinarily stiff [4] and their electrical conductivity can be very large. [4,5] Furthermore, ensembles of such nanotubes are useful aerogel precursors: they form electrically percolating networks at very low volume fractions [6] and elastic gels in concentrated suspensions through van der Waals interaction mediated cross-linking. [7,8] Here we report the creation of CNT aerogels from aqueousgel precursors by CPD and freeze-drying. CNT aerogels have been produced previously as intermediate phases during the process of drawing nanotube fibers [9] from a furnace and during the process of making sheets from multiwall CNT forests.[10] By contrast, our aerogels were derived directly from CNT networks in suspension, and we could readily manipulate the network properties as a result. The flexibility afforded by this process enabled us to control CNT concentration, to utilize optimized CNT dispersion processes, [11] to reinforce the networks with, for example, polyvinyl alcohol (PVA), and to infiltrate or backfill them with polymeric fluids. Here we describe these CNT aerogels and the processing methodologies used to synthesize them, and we characterize their electrical and mechanical properties. The CNT aerogels supported thousands of times their own weight after PVA-reinforcement, and, depending on processing conditions, their electrical conductivity ranged as high as ca. 1 S cm -1. Although our starting chemical vapor deposition (CVD) nanotube material contained single-and few-wall CNTs (the latter being predominantly double-wall CNTs, DWNTs), the dispersion and preparation processes employed here are directly applicable to pure single-wall CNTs (SWNTs).[11] CNT aerogel electrical and structural properties are also expected to be similar to pure SWNT samples because the electrical [12] and tensile [13] properties of bulk SWNTs and DWNTs are comparable. Images of typical critical-point-dried aerogels are seen in Figure 1. Unreinforced aerogels were fragile, but strong enough to permit careful handling. Reinforceme...

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mentioning

confidence: 99%

Carbon Nanotube Aerogels

et al. 2007

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“…Since the temperature differential between the hot and cold side of the heat transfer surface is only 7-9 'F (4-5 "C), the required energy and rates of scale formation are both low. A typical MVC system consumes - [30][31][32][33][34][35][36][37][38][39][40][41]. See Table 1 for published energy requirements for SW desalination processes [2].…”

Section: Thermal Processesmentioning

confidence: 99%

“…Note that thermal and chemical activation has been used to achieve BET surface areas of 1.3x107 ft2 lb-l (2600 m2 g-*) [32]. Resorcinol-formaldehyde (RF) aerogels and their carbonized derivatives were first developed by LLNL [33][34][35][36]. Monolithic sheets of this material were made by inlltrating a resorcinolformaldehyde solution into a porous carbon paper (Textron Specialty Materials, Lowell, MA), curing the wetted paper between glass plates in a closed vessel, and then pyrolyzing in an inert atmosphere.…”

Section: Carbon Aerogel Electrodesmentioning

confidence: 99%

Desalination with Carbon Aerogel Electrodes

Farmer¹,

Richardson²,

Fix³

et al. 1996

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“…In contrast, the differential pressure across four stacks in series As previously discussed, electrodes are made from thin sheets of CAC glued to titanium plates with conductive epoxy. Carbon aerogels were developed at Lawrence Livermore National Laboratory and are synthesized by the polycondensation of resorcinol and formaldehyde in a slightly basic medium, followed by supercritical dryins and pyrolysis in an inert atmosphere [26,27]. Sheets of CAC are made by impregnating carbon cloth with the resorcinol-formaldehyde solution and then carbonizing.…”

Section: 1~0~mentioning

confidence: 99%