Comparative pore structure analysis of highly porous graphene monoliths treated at different temperatures with adsorption of N2 at 77.4 K and of Ar at 87.3 K and 77.4 K

Wang, Shuwen; Minami, Daiki; Kaneko, Katsumi

doi:10.1016/j.micromeso.2015.01.014

Cited by 33 publications

(22 citation statements)

References 47 publications

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“…Without a quadrupole moment and with a smaller diameter (0.335 nm compared with 0.363 nm), Ar atoms can access small micropores more easily than N 2 . Combined with a higher experimental measurement temperature and a simpler theoretical analysis, this makes Ar adsorption at 87 K more suited than N 2 for the characterization of microporous carbons 13 . A complementary approach involves using the adsorption of supercritical gas or subcritical uids (CO 2 ) at ambient temperature, which improves the adsorption kinetics.…”

Section: Electrochemical Double-layer Capacitorsmentioning

confidence: 99%

Efficient storage mechanisms for building better supercapacitors

et al. 2016

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International audienceSupercapacitors are electrochemical energy storage devices that operate on the simple mechanism of adsorption of ions from an electrolyte on a high-surface-area electrode. Over the past decade, the performance of supercapacitors has greatly improved, as electrode materials have been tuned at the nanoscale and electrolytes have gained an active role, enabling more efficient storage mechanisms. In porous carbon materials with subnanometre pores, the desolvation of the ions leads to surprisingly high capacitances. Oxide materials store charge by surface redox reactions, leading to the pseudocapacitive effect. Understanding the physical mechanisms underlying charge storage in these materials is important for further development of supercapacitors. Here we review recent progress, from both in situ experiments and advanced simulation techniques, in understanding the charge storage mechanism in carbon- and oxide-based supercapacitors. We also discuss the challenges that still need to be addressed for building better supercapacitors

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Section: Electrochemical Double-layer Capacitorsmentioning

confidence: 99%

Efficient storage mechanisms for building better supercapacitors

et al. 2016

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“…The apparent SSA of the electrodes was evaluated by Brunauer-Emmet-Teller (BET) analysis [110] of physisorption measurements using Kr at 87 K ( Figure S5) [111][112][113][114] . Since the quadrupole moment of N 2 (0.27 e × 10 − 16 esu) [115] confines the access of the gas to micropores [ 111 , 113 , 114 ], Kr was preferred to N 2 in this experiment.…”

Section: Morphological Characterization Of the Electrodesmentioning

confidence: 99%

Scalable spray-coated graphene-based electrodes for high-power electrochemical double-layer capacitors operating over a wide range of temperature

Garakani

Bellani

Pellegrini

et al. 2021

Energy Storage Materials

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Advancements in electrochemical double-layer capacitor (EDLC) technology require the concomitant use of novel efficient electrode materials and viable electrode manufacturing methods. Cost-effectiveness, scalability and sustainability are key-drivers for fulfilling product development chain accepted by worldwide legislations. Herein, we report a scalable and sprayable "green " electrode material-based ink based on activated carbon and single-/fewlayer graphene (SLG/FLG) flakes. We show that, contrary to commercial reduced graphene oxide, defect-free and flat SLG/FLG flakes reduce the friction of ions over the electrode films, while spray coating deposition of our ink maximises the electrolyte accessibility to the electrode surface area. Sprayed SLG/FLG flakes-based EDLCs display superior rate capability performance (e.g. , specific energies of 31.5, 23.7 and 12.5 Wh kg − 1 at specific powers of 150, 7500 and 30000 W kg − 1 , respectively) compared to both SLG/FLG flakes-free devices and commercial-like EDLCs produced by slurry-coating method. The use of SLG/FLG flakes enables our sprayed EDLCs to operate in a wide range of temperature (− 40/ + 100°C) compatible with ionic liquid/organic solvent-based electrolytes, overcoming the specific power limits of AC-based EDLCs. A prototype EDLCs stack consisting of multiple large-area EDLCs, each one displaying a capacitance of 25 F, demonstrates the industrial potential of our technology.

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“…Particularly in the case of nanomaterials such as carbon nanotubes and graphenes, porosity can result in possible occurrences of thin-layer diffusion and/or adsorption effects [1,10,11,14,[20][21][22] due to internal pore structures and the concomitant surface area increase [23]. However, there also remains uncertainty over the general extent to which porosity (as an extrinsic property) can influence experimental data, and which may consequently result in erroneous interpretations of apparent enhancements arising from intrinsic material properties.…”

Section: Accepted Manuscriptmentioning

confidence: 99%