Thermal and electrical conductivity of monolithic carbon aerogels

Lu, X.; Nilsson, Ove; Fricke, J.; Pekala, R.W.

doi:10.1063/1.353367

Cited by 193 publications

(124 citation statements)

References 14 publications

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“…31,32 It is also noted that the tortuous conduction pathway in porous carbon means that conductivity scales directly with density. 33 It follows that the less dense, porous CP films will show a reduced conductivity than the denser SP films.…”

Section: Resultsmentioning

confidence: 99%

The Role of Unbound Oligomers in the Nucleation and Growth of Electrodeposited Polypyrrole and Method for Preparing High Strength, High Conductivity Films

et al. 2012

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Polypyrrole is a material with immensely useful properties suitable for a wide range of electrochemical applications, but its development has been hindered by cumbersome manufacturing processes. Here we show that a simple modification to the standard electrochemical polymerization method produces polypyrrole films of equivalently high conductivity and superior mechanical properties in one-tenth of the polymerization time. Preparing the film as a series of electrodeposited layers with thorough solvent washing between layering was found to produce excellent quality films even when layer deposition was accelerated by high current. The washing step between the sequentially polymerized layers altered the deposition mechanism, eliminating the typical dendritic growth and generating nonporous deposits. Solvent washing was shown to reduce the concentration of oligomeric species in the near-electrode region and hinder the three-dimensional growth mechanism that occurs by deposition of secondary particles from solution. As artificial muscles, the high density sequentially polymerized films produced the highest mechanical work output yet reported for polypyrrole actuators. ABSTRACT: Polypyrrole is a material with immensely useful properties suitable for a wide range of electrochemical applications, but its development has been hindered by cumbersome manufacturing processes. Here we show that a simple modification to the standard electrochemical polymerization method produces polypyrrole films of equivalently high conductivity and superior mechanical properties in onetenth of the polymerization time. Preparing the film as a series of electrodeposited layers with thorough solvent washing between layering was found to produce excellent quality films even when layer deposition was accelerated by high current. The washing step between the sequentially polymerized layers altered the deposition mechanism, eliminating the typical dendritic growth and generating nonporous deposits. Solvent washing was shown to reduce the concentration of oligomeric species in the near-electrode region and hinder the three-dimensional growth mechanism that occurs by deposition of secondary particles from solution. As artificial muscles, the high density sequentially polymerized films produced the highest mechanical work output yet reported for polypyrrole actuators.

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Section: Resultsmentioning

confidence: 99%

The Role of Unbound Oligomers in the Nucleation and Growth of Electrodeposited Polypyrrole and Method for Preparing High Strength, High Conductivity Films

et al. 2012

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“…Batterie-ähnliche Superkondensatoren: Poröse Metalle mit großen Oberflächen könnten hergestellt werden, die die Leitfähigkeit ultraporöser Kohlenstoffelektroden, wie sie heute in Superkondensatoren (Ultrakondensatoren) eingesetzt werden, [43,44] übertreffen. Sie könnten außerdem so optimiert werden, dass eine bessere Benetzung durch Elektrolyte und infolgedessen höhere Doppelschichtkapazitäten an der Elektrodenoberfläche erreicht werden, was unmittelbar zu höheren Energiedichten führt.…”

Section: Technisches Potenzial Nanoporöser Metallschäumeunclassified

Nanoporöse Metallschäume

2010

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Nanoporöse Metallschäume (NMFs) werden seit langem als eine Klasse von Stoffen für leitfähige und katalytische Materialien mit großen Oberflächen untersucht. Dieser Aufsatz gibt einen Überblick über neue Strategien für die Herstellung von NMFs mit einem Schwerpunkt auf der Verbrennungssynthese und diskutiert aktuelle Anwendung von NMFs, unter anderem zur Speicherung von Wasserstoff und in der Katalyse.

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“…The conductive heat transport for temperatures above 100 K was described as a diffusion process, since a proportionality between specific heat and thermal conductivity could be established if contributions of phonons and localized modes are negligible or can be corrected for [12,13]. In addition, scaling of the thermal conductivity of silica and organic aerogels as well as the electrical conductivity of carbon aerogels upon variation of density were observed [14,15]. Likewise, many articles on the elastic properties of gel networks have been published.…”

Section: Introductionmentioning

confidence: 95%

“…The experimental setup for the determination of the elastic modulus and the thermal and electrical conductivity as well as the preparation of the sample series presented here are given in the respective references [12,14,15,32], from which the data were taken. Small angle X-ray scattering (SAXS) measurements using either the synchrotron SAXS-beamline B 1 at HASYLAB/DESY (Hamburg) or a Kratky camera were performed in order to characterize the morphology of the aerogel network via the mass fractal dimension D.…”

Section: Introductionmentioning

confidence: 99%

Scaling properties and structure of aerogels

Emmerling

Fricke

1997

J Sol-Gel Sci Technol

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Abstract. Young's modulus as well as solid thermal and electrical conductivitiy of aerogels have been observed to scale with density. No quantitative explanations were available up to now for these experimental findings. To establish a quantitive relationship between morphological and topological features of fractal gel networks, a simulation procedure is introduced that allows to produce three-dimensional gel structures, from which two important parameters can be extracted: i) the fraction o~ of interconnected mass of the gel network and ii) the ratio y of Pythagorean distance to minimum path length on the gel backbone. Surprisingly the product o~),, which enters important macroscopic parameters such as elasticity or solid thermal (and electrical) conductivity, was found to scale with an exponent that is only a function of the mass fractal dimension D. Also, an analytical relation between modulus and conductivity can be derived.

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Thermal and electrical conductivity of monolithic carbon aerogels

Cited by 193 publications

References 14 publications

The Role of Unbound Oligomers in the Nucleation and Growth of Electrodeposited Polypyrrole and Method for Preparing High Strength, High Conductivity Films

The Role of Unbound Oligomers in the Nucleation and Growth of Electrodeposited Polypyrrole and Method for Preparing High Strength, High Conductivity Films

Nanoporöse Metallschäume

Scaling properties and structure of aerogels

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