Carbon aerogels for electrochemical applications

Pekala, R.W.; Farmer, Joseph C.; Alviso, C.T.; Tran, Tri; Mayer, S.T.; Miller, J.; Dunn, Bruce

doi:10.1016/s0022-3093(98)00011-8

Cited by 524 publications

(291 citation statements)

References 10 publications

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“…methanol), the water and the methanol contained in the formaldehyde solution are also taken into account to calculate D. Should no shrinkage occur during drying, this choice would lead to dried materials with a bulk density equal to 0.35 g/cm 3 , and a pore volume close to 2.2 cm³/g [18]. In our previous studies [16,17,19], the gel texture was fixed by adjusting the pH of the resorcinol-formaldehyde solution with…”

Section: Gels Synthesis and Dryingmentioning

confidence: 99%

“…In particular, porous carbons derived from drying and pyrolysis of these gels are promising for many applications. The high specific surface areas and conductivity obtained make these materials good candidates for the elaboration of electrodes for supercapacitors, batteries or fuel cells [3][4][5]; the low thermal conductivities observed are interesting for the development of thermal insulators; the ability to tailor the pore texture of the carbon materials is a great advantage in the fields of adsorption and catalysts supports [6][7][8]. However, the original process developed by Pekala is long and very difficult to apply at large scale.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis optimization of organic xerogels produced from convective air-drying of resorcinol–formaldehyde gels

Job

Panariello

Marien

et al. 2006

Journal of Non-Crystalline Solids

110

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Resorcinol-formaldehyde gels were produced at 50, 70 and 90°C and with three different R/C ratios (500, 1000 and 2000). The effect of these variables combined with that of aging time was studied in order to optimize the synthesis conditions. The convective air-drying process was used, and the drying duration was studied with regard to the synthesis conditions. The aging time has no effect on the pore texture after 24 h at 90°C or 48 h at 70°C, whatever the R/C value. The synthesis-aging step can be shortened by increasing the temperature.Nevertheless, the pore size tends then to decrease, especially when R/C is high, but this can be counterbalanced by increasing R/C. Moreover, bubbles often appear in the gel at high synthesis temperature, which limits the temperature to about 70°C in the case of monolithic parts. At 70°C and with an air velocity of 2 m/s, the elimination of 90% of the solvent Manuscript 2 requires 1 h drying when the pore size reaches 400-600 nm, 2.5 h for 50 nm wide pores and 3 h when the pore size decreases to 15-20 nm. The drying duration does not exceed 8 h in all cases and could be shortened by increasing the temperature at the end of the process.

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Section: Gels Synthesis and Dryingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis optimization of organic xerogels produced from convective air-drying of resorcinol–formaldehyde gels

Job

Panariello

Marien

et al. 2006

Journal of Non-Crystalline Solids

110

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“…Supercritical conditions are used to preserve the pore texture, by avoiding surface tensions and shrinkage due to the appearance of liquid-vapour interfaces. With their large mesopore volumes (> 0.89 cm³/g) and high specific surface areas (500-1200 m²/g), potential applications of carbon aerogels are numerous: adsorbents for gas separation [3] and [4], catalysts supports [5], [6] and [7,7], electrode material for double layer capacitors [8], [9] and [10], energy storage device [11], column packing materials for chromatography,……”

Section: Introductionmentioning

confidence: 99%

“…Monolithicity is one of the crucial properties of RF xerogels needed for many applications like electrodes or supercapacitors [10], [11], [19], [20] and [21]. For those applications a fixed shape and size of xerogels is required.…”

Section: Introductionmentioning

confidence: 99%

Evolution of mechanical properties and final textural properties of resorcinol–formaldehyde xerogels during ambient air drying

Léonard

Blacher

Crine

et al. 2008

Journal of Non-Crystalline Solids

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Porous carbon xerogels can be obtained by convective drying of resorcinol (R)-formaldehyde (F) hydrogels, followed by pyrolysis. Drying conditions have to be carefully controlled when crack-free monoliths with well-defined shape and size are required. The knowledge of the mechanical properties of the RF xerogels and their evolution with water content is essential to model their thermo-hygro-mechanical behaviour during convective drying and avoid mechanical stresses leading to deformation and cracking of the sample. The shrinkage behaviour and the mechanical properties of RF xerogels obtained with R/C ratio ranging from 300 to 1500 were investigated. R/C greatly influences the shrinkage and mechanical properties of the wet gel, on the one hand, and the mechanical and textural properties of the dried gel, on the other hand. The smaller the R/C, the higher the shrinkage, the stiffening, and the viscoelastic character of the xerogels. Water content has an influence on both the stiffness of the gels and the viscoelastic response. Generally, samples lose their mechanical viscous character and become more rigid when they are dried. Finally, mercury porosimetry measurements showed that the gels exhibit a marked lowering of 2 their stiffness upon compression, interpreted as a result of the heterogeneity of the microstructure.

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“…More development in porous structure of 2S2-900 sample can be observed more clearly by its nitrogen adsorption-desorption isotherms and pore size distribution compared to that of 2S1-900 sample in Figures 2 and 3. It indicates that the continuous solvent exchange process by fresh acetone immediately after finishing the gelation process plays an important role in maintaining mesopores due to reducing the surface tensions upon drying in ambient conditions; it leads to restriction of the collapse of the weak gel network [16,17], which on the carbonization slowly generates carbon porosity. From the above investigated results, the RC ratio of 2 and acetone exchange after every 3 hours during the first day were selected for preparation conditions of carbon xerogels in the next investigation.…”

Section: Characterization Of Materialmentioning

confidence: 99%

Investigation of the Characteristic Properties of Glacial Acetic Acid-Catalyzed Carbon Xerogels and Their Electrochemical Performance for Use as Electrode Materials in Electrical Double-Layer Capacitors

Quach

Yang

Chung

et al. 2017

Advances in Materials Science and Engineering

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Glacial acetic acid was used as a catalyst in the preparation process of carbon xerogels from the condensation of resorcinol and formaldehyde for shortening significantly the gelation time. The effect of the resorcinol/catalyst ratio over a large range of 2 to 500, the solvent exchange manner with acetone, and the pyrolysis temperature of 700 to 1000 ∘ C on the characteristic properties of the carbon xerogels were investigated. A resorcinol/catalyst ratio of 2 and a pyrolysis temperature at 800 ∘ C were found to be the optimal condition for the preparation of carbon xerogels with a well-balanced porosity between micro-and mesopores, high surface area (577.62 m 2 g −1 ), and large pore volume (0.97 cm 3 g −1 ), which are appropriate for use as electrode materials in an electrical double-layer capacitor. The carbon xerogel electrodes that were prepared under these optimal conditions exhibited a good electrochemical performance with the highest specific capacitance of 169 Fg −1 in 6 M KOH electrolyte at a scan rate of 5 mVs −1 from cyclic voltammetry.

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Carbon aerogels for electrochemical applications

Cited by 524 publications

References 10 publications

Synthesis optimization of organic xerogels produced from convective air-drying of resorcinol–formaldehyde gels

Synthesis optimization of organic xerogels produced from convective air-drying of resorcinol–formaldehyde gels

Evolution of mechanical properties and final textural properties of resorcinol–formaldehyde xerogels during ambient air drying

Investigation of the Characteristic Properties of Glacial Acetic Acid-Catalyzed Carbon Xerogels and Their Electrochemical Performance for Use as Electrode Materials in Electrical Double-Layer Capacitors

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