Influence of the textural parameters of resorcinol–formaldehyde dry polymers and carbon xerogels on particle sizes upon mechanical milling

Piedboeuf, Marie-Laure; Léonard, A.; Traina, Karl; Job, Nathalie

doi:10.1016/j.colsurfa.2015.02.014

Cited by 21 publications

(20 citation statements)

References 28 publications

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“…This sequence was performed in the low-pressure range (0.2-400 kPa) using PASCAL 140 and in the high-pressure range (up to 200 MPa) using PASCAL 240, providing the mercury intrusion volume at different equilibrated mercury pressures. The cumulative pore volumes of EDLC electrodes were calculated using the Washburn equation [42] with aid from a software installed in the above mercury porosimeter, where the shape of pores were assumed to be a cylinder.…”

Section: Electrochemical Characterizationmentioning

confidence: 99%

Effect of Ball Milling on the Electrochemical Performance of Activated Carbon with a Very High Specific Surface Area

et al. 2020

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Activated carbon (AC) with a very high specific surface area of >3000 m2 g−1 and a number of course particles (average size: 75 µm) was pulverized by means of planetary ball milling under different conditions to find its greatest performances as the active material of an electric double-layer capacitor (EDLC) using a nonaqueous electrolyte. The variations in textural properties and particle morphology of the AC during the ball milling were investigated. The electrochemical performance (specific capacitance, rate and cyclic stabilities, and Ragone plot, both from gravimetric and volumetric viewpoints) was also evaluated for the ACs milled with different particle size distributions. A trade-off relation between the pulverization and the porosity maintenance of the AC was observed within the limited milling time. However, prolonged milling led to a degeneration of pores within the AC and a saturation of pulverization degree. The appropriate milling time provided the AC a high volumetric specific capacitance, as well as the greatest maintenance of both the gravimetric and volumetric specific capacitance. A high volumetric energy density of 6.6 Wh L−1 was attained at the high-power density of 1 kW L−1, which was a 35% increment compared with the nonmilled AC. The electrode densification (decreased interparticle gap) and the enhanced ion-transportation within the AC pores, which were attributed to the pulverization, were responsible for those excellent performances. It was also shown that excessive milling could degrade the EDLC performances because of the lowered micro- and meso-porosity and the excessive electrode densification to restrict the ion-transportation within the pores.

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Section: Electrochemical Characterizationmentioning

confidence: 99%

Effect of Ball Milling on the Electrochemical Performance of Activated Carbon with a Very High Specific Surface Area

et al. 2020

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“…A part of the dried xerogel is then ground using a Fritsch planetary mill (Mono Mill P6) in agate jars with 1 cm diameter balls following the procedure described in a previous work to obtain homogenous and reproducible particle sizes [43]. Afterwards the grinded powder is pyrolyzed under nitrogen at 800°C following [41], this way is called the dry way of grinding.…”

Section: Xerogel Synthesis and Grindingmentioning

confidence: 99%

“…The second part of dried powder is directly pyrolyzed under nitrogen at 800°C following the program detailed in reference [41]; the obtained carbon is then grinded with isopropanol using a Retsch PM 400 planetary mill in zirconium oxide jars with 1 mm diameter balls, leading to the liquid way of grinding.…”

Section: Xerogel Synthesis and Grindingmentioning

confidence: 99%

A practical method to characterize proton exchange membrane fuel cell catalyst layer topography: Application to two coating techniques and two carbon supports

et al. 2020

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The coating technique and the type of carbon support can strongly affect the surface topography, the homogeneity and the thickness of the catalyst layers of Proton Exchange Membrane fuel cells. These features can in turn strongly modify the local diffusion properties of the layer and the final cell performance, but literature about catalytic layers does not often address such issues. This work aims at studying the topography of proton exchange membrane fuel cell catalyst layers by means of 3D characterization methods. For that purpose, two types of slurries, made of Nafion Ⓡ and carbon black or a carbon xerogel, have been coated on a Kapton Ⓡ sheet by film-casting and by spray-coating. The surface topography of the samples was characterized by contact profilometry and 3D laser scanning microscopy. The data obtained with both methods were processed in order to obtain accurate 3D representations of the surface of the layers. Contact profilometry allows to perform measurements over the entire surface of the sample (5 cm × 5 cm). Layers obtained by film-casting turn out to be very smooth, but also thinner at the edges of the coating. For layers prepared by spray-coating, the reproducibility and the homogeneity are improved; however, the surface displays a higher roughness. With 3D laser scanning microscopy measurements, only a small part of the sample was analyzed (0.25 cm 2) with a high definition, allowing to characterize more precisely the surface topography. The comparison of both techniques has been enriched by the simulation of the profilometer tip motion at the surface of the observed 3D microscopy profile, giving insight into the observed differences. The 3D microscopy measurements proved to be more accurate, but not representative of the whole sample, especially for less homogeneous layers prepared by filmcasting.

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“…These texture and specific surface area changes are more obvious for bead samples because the gel surface in contact with oleic acid is about 20 times higher for beads than for monolithic samples. XABbp sample displays the lowest specific surface area (241 m 2 /g) whereas MXA has a specific surface area of 657 m 2 /g; this indicates that the milling‐binding process probably damages the pores by sealing them with alginates residues, given that previous studies showed that the specific surface area is not significantly reduced by milling . Moreover, after subsequent pyrolysis, sample XAB displays a specific surface area of 624 m 2 /g, which is almost similar to MXA (657 m 2 /g).…”

Section: Discussionmentioning

confidence: 75%

Toward a continuous synthesis of porous carbon xerogel beads

et al. 2018

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A continuous process for producing porous carbon xerogel beads has been developed. It consists in injecting a pre‐cured aqueous solution of resorcinol and formaldehyde on top of a column filled with hot oleic acid. The latter is pumped on the top of the column and fed at the bottom, generating an upward flow that can be adjusted to match the terminal velocity of the settling beads. Thus, the bead residence time in the column can be adjusted to match the gelation time, allowing the beads to solidify before reaching the bottom of the vessel. The obtained beads are subsequently dried and pyrolyzed. The developed experimental setup proved the continuous synthesis of porous carbon beads is possible. Nevertheless, the shaping process caused various texture changes of the porous carbon, which mainly yields macropores instead of micro and mesopores. This process also leads to the build‐up of a denser skin around the beads. © 2018 American Institute of Chemical Engineers AIChE J, 64: 1049–1058, 2018

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Influence of the textural parameters of resorcinol–formaldehyde dry polymers and carbon xerogels on particle sizes upon mechanical milling

Cited by 21 publications

References 28 publications

Effect of Ball Milling on the Electrochemical Performance of Activated Carbon with a Very High Specific Surface Area

Effect of Ball Milling on the Electrochemical Performance of Activated Carbon with a Very High Specific Surface Area

A practical method to characterize proton exchange membrane fuel cell catalyst layer topography: Application to two coating techniques and two carbon supports

Toward a continuous synthesis of porous carbon xerogel beads

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