The effect of physical adsorption on the capacitance of activated carbon electrodes

Tolman, Nathan; Mukai, Jason; Wang, Shuqing; Zito, Alessandra; Luo, Tian‐Yi; Liu, Haitao

doi:10.1016/j.carbon.2019.05.005

Cited by 9 publications

(18 citation statements)

References 20 publications

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“…For FM10AC, an expanded interlayer comparable to that of GO–CNT is also evident, which may indicate a commercial proprietary treatment of activated carbon, because the expected diffraction pattern should express broad X-ray reflections between 20–30° and 40–45° . For the purposes of revealing the capacitive behavior of FM10AC, a prior study demonstrated the feasibility of an analogous activated carbon cloth for EDL measurements . For FM10AC_CTS, an overall diffraction pattern reminiscent of typical carbon black is observed, with the presence of graphitic crystallites at 27°.…”

Section: Resultsmentioning

confidence: 92%

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Rapid Carbothermal Shock Enhances the Double-Layer Response of Graphene Oxide–Carbon Nanotube Electrodes

Meng

Elazar-Mittelman

et al. 2021

Energy Fuels

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Graphene oxide and carbon nanotube composites are considered to be an ideal electrode for electrochemical energy storage and conversion. Herein, we prepare electrodes via a green synthesis that yields a binderless, flexible, and free-standing electrode. To improve the performance of these electrodes comprising graphene oxide and carbon nanotubes (GO−CNT), we carry out carbothermal shock (CTS), which reduces graphene oxide in a rapid (millisecond time scale) and tunable manner (1000−2000 K). When CTS is employed, the specific capacitance of GO−CNT increases by 50%, from 30 to 45 F g −1 , for reduced GO−CNT (GO−CNT_CTS). When benchmarking against activated carbon, both GO−CNT and GO−CNT_CTS outperform in terms of capacitance and rate capability. We then examine impedance spectroscopy data in the form of two-dimensional colormapped surface plots to analyze the dependence of the real and imaginary capacitance and the phase angle as a function of both frequency and potential. This analysis provides key mechanistic insight into the electrochemical double-layer response, such as the characteristic relaxation time and charge-transfer resistance. This analysis shows that, upon CTS, the relaxation times of GO−CNTbased electrodes are 70% faster than that of activated carbon and charge-transfer resistances are reduced dramatically.

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Section: Resultsmentioning

confidence: 92%

“…67 For the purposes of revealing the capacitive behavior of FM10AC, a prior study demonstrated the feasibility of an analogous activated carbon cloth for EDL measurements. 68 For FM10AC_CTS, an overall diffraction pattern reminiscent of typical carbon black is observed, 69 with the presence of graphitic crystallites at 27°.…”

Section: ■ Results and Discussionmentioning

confidence: 97%

Rapid Carbothermal Shock Enhances the Double-Layer Response of Graphene Oxide–Carbon Nanotube Electrodes

Meng

Elazar-Mittelman

et al. 2021

Energy Fuels

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“…This background drift of current density (dotted blue curve) varies between electrode samples, possibly because of nonuniform surface conditions of large-area graphene (e.g., contaminants, defect density, grain size, etc.). For example, we previously showed that HOPG surface slowly adsorbs hydrocarbon contaminants in water, reducing its double-layer capacitance and electrochemical activity. − The contaminants on the graphene surface can be also lifted off from the surface as H 2 gas bubbles form on the surface of graphene during HER. Nevertheless, despite the background drift of the current density throughout the measurements, a sharp change in current density is observed in response to the change in the applied strain (Figure a).…”

Section: Resultsmentioning

confidence: 99%

Real-Time Modulation of Hydrogen Evolution Activity of Graphene Electrodes Using Mechanical Strain

Kim

Sorescu

Amemiya

et al. 2022

ACS Appl. Mater. Interfaces

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This paper reports the effect of mechanically applied elastic strain on the hydrogen evolution reaction (HER) activity of graphene under acidic conditions. An applied tensile strain of 0.2% on a graphene electrode is shown to lead to a 1−3% increase in the HER current. The tensile strain increases HER activity, whereas compressive strain decreases it. Density functional theory (DFT) calculations using a periodic graphene slab model predict an increase in the adsorption energy of the H atom with growing tensile strain, consistent with an enhancement of the current density in HER, similar to that observed experimentally.

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“…The 2D nanosheets usually share high specific surface areas, exhibit abundant active sites for electrochemical reactions, and offer widespread platforms to charge transport. , Large specific surface areas of 2D carbon materials are beneficial for improving reaction kinetics in many electrochemical processes, on account of the dominant capacitance contribution. , Recently, Huang et al designed N-self-doped porous carbon (NPC) sheets as carrier materials of S for ambient Na-ion storage . Benefiting from their large specific surface area, the NPC sheets were demonstrated to be ideal sulfur hosts for RT Na–S batteries.…”

Section: Morphological Modulationmentioning

confidence: 99%

Nanostructure Engineering Strategies of Cathode Materials for Room-Temperature Na–S Batteries

et al. 2022

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Room-temperature sodium−sulfur (RT Na−S) batteries are considered to be a competitive electrochemical energy storage system, due to their advantages in abundant natural reserves, inexpensive materials, and superb theoretical energy density. Nevertheless, RT Na−S batteries suffer from a series of critical challenges, especially on the S cathode side, including the insulating nature of S and its discharge products, volumetric fluctuation of S species during the (de)sodiation process, shuttle effect of soluble sodium polysulfides, and sluggish conversion kinetics. Recent studies have shown that nanostructural designs of S-based materials can greatly contribute to alleviating the aforementioned issues via their unique physicochemical properties and architectural features. In this review, we review frontier advancements in nanostructure engineering strategies of S-based cathode materials for RT Na−S batteries in the past decade. Our emphasis is focused on delicate and highly efficient design strategies of material nanostructures as well as interactions of component−structure−property at a nanosize level. We also present our prospects toward further functional engineering and applications of nanostructured S-based materials in RT Na−S batteries and point out some potential developmental directions.

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The effect of physical adsorption on the capacitance of activated carbon electrodes

Cited by 9 publications

References 20 publications

Rapid Carbothermal Shock Enhances the Double-Layer Response of Graphene Oxide–Carbon Nanotube Electrodes

Rapid Carbothermal Shock Enhances the Double-Layer Response of Graphene Oxide–Carbon Nanotube Electrodes

Real-Time Modulation of Hydrogen Evolution Activity of Graphene Electrodes Using Mechanical Strain

Nanostructure Engineering Strategies of Cathode Materials for Room-Temperature Na–S Batteries

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