Understanding the rate performance of microporous carbons in aqueous electrolytes

Aldama, I.; Lillo-Ródenas, M.A.; Kunowsky, Mirko; Ibáñez, Joaquı́n; Rojo, J. M.

doi:10.1016/j.electacta.2020.136408

Cited by 4 publications

(3 citation statements)

References 78 publications

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“…Interestingly, the polarity matching with 6 M KOH solution was not as effective as that with EMIM-TFSI; most likely because K + and OH − ions (∼0.33 nm) are much smaller than EMIM + and TFSI − ions (∼0.9 nm), 86,87 leading to ∼100 times higher ionic conductivity of the aqueous electrolyte than the ionic liquid. 88,89 Consequently, the superwettability of the electrode−electrolyte interface plays a major role when electrolyte ions are sterically demanding and cannot easily access surface micropores to facilitate ionic diffusion.…”

Section: Discussionmentioning

confidence: 99%

“…In the presence of nonpolar EMIM-TFSI, in particular, the EDLCs containing superhydrophobic 3D GFs displayed ≥548 times higher capacitance at ≥0.5 A g –1 than those containing superhydrophilic ones, leading to the capacitance of more than 133.7 F g –1 at ≤0.1 A g –1 . Interestingly, the polarity matching with 6 M KOH solution was not as effective as that with EMIM-TFSI; most likely because K + and OH – ions (∼0.33 nm) are much smaller than EMIM + and TFSI – ions (∼0.9 nm), , leading to ∼100 times higher ionic conductivity of the aqueous electrolyte than the ionic liquid. , Consequently, the superwettability of the electrode–electrolyte interface plays a major role when electrolyte ions are sterically demanding and cannot easily access surface micropores to facilitate ionic diffusion.…”

Section: Discussionmentioning

confidence: 99%

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Ultrafast and Reversible Superwettability Switching of 3D Graphene Foams via Solvent-Exclusive Plasma Treatments

Cheon,

Cho,

et al. 2024

ACS Nano

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For highly active electron transfer and ion diffusion, controlling the surface wettability of electrically and thermally conductive 3D graphene foams (3D GFs) is required. Here, we present ultrasimple and rapid superwettability switching of 3D GFs in a reversible and reproducible manner, mediated by solvent-exclusive microwave arcs. As the 3D GFs are prepared with vapors of nonpolar acetone or polar water exclusively, short microwave radiation (≤10 s) leads to plasma hotspot-mediated production of methyl and hydroxyl radicals, respectively. Upon immediate radical chemisorption, the 3D surfaces become either superhydrophobic (water contact angle = ∼170°) or superhydrophilic (∼0°), and interestingly, the wettability transition can be repeated many times due to the facile exchange between previously chemisorbed and newly introduced radicals via the formation of methanol-like intermediates. When 3D GFs of different surficial polarities are incorporated into electric doublelayer capacitors with nonpolar ionic liquids or polar aqueous electrolytes, the polarity matching between graphene surfaces and electrolytes results in ≥548.0 times higher capacitance compared to its mismatching at ≥0.5 A g −1 , demonstrating the significance of wettability-controlled 3D GFs.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Ultrafast and Reversible Superwettability Switching of 3D Graphene Foams via Solvent-Exclusive Plasma Treatments

Cheon,

Cho,

et al. 2024

ACS Nano

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“…[20][21][22][23] Despite their limited voltage window, aqueous electrolytes are widely used because of their higher conductivity in addition to their cost-effectiveness and ease of manufacturing. 20,24 Monte Carlo simulations performed to investigate the formation of EDLs of electrolyte mixtures inside slit nanopores have revealed that the competition between charge and ion size has significant effects on electrolyte distribution in charged cavities. 25,26 Using DFT, Henderson et al 27 investigated the capacitance of a charged hard sphere system near a planar charged surface to find that the minimum capacitance observed at a low ionic density and a small electrode charge converts to a maximum in the capacitance curve with increasing ion density.…”

mentioning

confidence: 99%

Ionic Competition over Adsorption into Charged Spherical Cavities Affecting the Shape of Electric Double Layer Capacitance Curve and Zeta Potential: A Density Functional Theory Study

Keshavarzi

Safdaar

2021

J. Electrochem. Soc.

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Modified fundamental measure theory in framework of restricted primitive model is employed to investigate the formation of the electric double layer at the concave wall of a charged spherical cavity when two positive ions, A + and C 2+, are in competition. Results indicate that, compared to A + at a bulk concentration 1M, the presence of even low concentrations (0.01 M) of C 2+ leads to a remarkable change in the capacitance curve’s shape. The concentration plays an important role in ionic adsorption at low values of electric potential, EP, while the ion charge has a dominant role at high enough EPs. The mole fraction of A + ions in the cavity, shows an initial increase with EP because of their higher concentration but they are later desorbed from the cavity. Hence, shows a maximum at EP at which their substitution with C 2+ ions start. This maximum shifts to lower EP with increasing C 2+ concentration and cavity curvature. This substitution of ions leads to a remarkable change in the capacitance curve’s shape, converting the symmetric capacitance curve to an asymmetric one. The zeta potential whose value is effectively changed by this substitution, is investigated along with its role in the diffuse capacitance.

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Porous Hollow Biomass-Based Carbon Nanostructures for High-Performance Supercapacitors

Rawat

Jindal

Muto

et al. 2023

Green Energy and Technology

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Understanding the rate performance of microporous carbons in aqueous electrolytes

Cited by 4 publications

References 78 publications

Ultrafast and Reversible Superwettability Switching of 3D Graphene Foams via Solvent-Exclusive Plasma Treatments

Ultrafast and Reversible Superwettability Switching of 3D Graphene Foams via Solvent-Exclusive Plasma Treatments

Ionic Competition over Adsorption into Charged Spherical Cavities Affecting the Shape of Electric Double Layer Capacitance Curve and Zeta Potential: A Density Functional Theory Study

Porous Hollow Biomass-Based Carbon Nanostructures for High-Performance Supercapacitors

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