Surface chemistry of carbon electrodes in 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid – an in situ infrared study

Romann, Tavo; Oll, Ove; Pikma, Piret; Tamme, Hannes; Lust, Enn

doi:10.1016/j.electacta.2014.01.077

Cited by 63 publications

(67 citation statements)

References 39 publications

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“…2a (where the third CV curve for pure EMImBF 4 and the second CV curves for 1 or 5 wt% EMImI solutions in EMImBF 4 are shown). The smallest current densities have been measured for C(Mo 2 C) | pure EMImBF 4 interface within electrode potential (E) region from 0.00 to −1.50 V. At E ≤ −1.50 V, the electroreduction processes started (mainly dimerization of EMIm + cations and desorption of H 2 formed), giving a small reduction peak at E = −1.65 V marked as "E1", and the negative current increased exponentially at E < −1.75 V. 41 For 1 wt% EMImI in EMImBF 4 ( Fig. 2a, black line) the CV has very weakly disturbed ("noisy") shape within E from −1.10 to −1.65 V, caused by electroreduction of H 2 O residues and by formation of reaction intermediates or final products (i.e.…”

Section: Resultsmentioning

confidence: 99%

“…Region of exponential increase of current density has been shifted for 1 wt% I − anions containing solution due to the zero charge potential shift by I − adsorption. 32,33,35,[39][40][41] The smoother shape of CV curve for 5 wt% EMImI + EMImBF 4 mixture (Fig. 2a, dashed black line) and a very wide oxidation (reoxidation) peak at E = −0.75 V (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The formation of reaction intermediates 32,33,[39][40][41] and desorption of gas bubbles cause weak current disturbance at the working electrode surface being later notable in the CVs as electrochemical current pulsation ("noise"). 30 The electrochemical behavior of the negatively polarized C(Mo 2 C) electrode in pure EMImBF 4 , and 1 or 5 wt% EMImI containing EMImBF 4 solutions are characterized in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Very high specific capacitance values (from 75 to 175 F g −1 for aqueous and from 40 to 100 F g −1 for nonaqueous electrolytes based commercial EDLC cells, [1][2][3] and 100 -150 F g −1 for micro-mesoporous carbon electrodes or nonaqueous electrolytes and ionic liquid based EDLC cells [4][5][6][7][8][9][10] ) have been measured. These devices are also called as "supercapacitors" [1][2][3][11][12][13][14][15][16][17] and used as short term high electric power density systems or as filtering or stabilizing elements in the electric circuits.…”

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confidence: 99%

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Influence of Iodide Ions Concentration on the Stability of 1-Ethyl-3-methylimidazolium Tetrafluoroborate | Molybdenum Carbide Derived Carbon Electrode Interface

Kruusma

Tõnisoo

Pärna

et al. 2017

J. Electrochem. Soc.

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Influence of the iodide ions adsorption on the in situ measured X-ray photoelectron spectra of C 1s, N 1s, B 1s, F 1s and I 3d photoelectrons, indicating the changes in the chemical composition taking place at the carbon (C) | 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF 4 ) + 1-ethyl-3-methylimidazolium iodide mixed ionic liquids interface, has been studied. Simultaneously, the stability of the formed C electrode | ionic liquid interface has been analyzed electrochemically. Electroreduction of the BF 4 − anion seems to start at less negative potential than the 1-ethyl-3-methylimidazolium (EMIm + ) cation. Addition of the I − ions to the EMImBF 4 initiates the electrochemical processes at C electrode at lower negative or positive potentials. However, intensity of the electrochemical reduction of EMIm + cation was suppressed. The experiments, performed in the vacuum conditions, indicated that slow faradaic oxidation processes started already at E ≥ 1.0 V (vs. Ag/AgCl in EMImBF 4 ). Our investigations clearly show that the formed passivating layer at the carbon electrode is unstable and decomposes slowly producing gaseous products. Based on the analysis of results collected the electrode materials for electrochemical double layer capacitors should be tested in the vacuum conditions in order to detect the early start of very slow faradaic processes producing gaseous products. Electrochemical double layer capacitors (EDLCs) are one of the electric charge storage systems. Very high specific capacitance values (from 75 to 175 F g −1 for aqueous and from 40 to 100 F g −1 for nonaqueous electrolytes based commercial EDLC cells, 1-3 and 100 -150 F g −1 for micro-mesoporous carbon electrodes or nonaqueous electrolytes and ionic liquid based EDLC cells 4-10 ) have been measured. These devices are also called as "supercapacitors" 1-3,11-17 and used as short term high electric power density systems or as filtering or stabilizing elements in the electric circuits.12,14 It should be noted that the EDLCs are composed of various electrode materials and electrolyte solutions (ionic liquids and non-aqueous solutions are often used [14][15][16][17] ). The power density of an EDLC depends on the mobility of the electrolyte ions (on the electric conductivity of a system 13,14 ) and the specific capacitance depends on the total gravimetric area of the electrode. To expand the specific capacitance of an EDLC the electrochemically active area and/or the applicable cell potential should be increased, because the energy and power densities are root functions of the cell potential.1-17 However, the value of the maximum achievable electrochemically active specific area is limited by the optimal pore diameter determined by the size of the dissolved electrolyte ions (solvated or partially desolvated 8 ) and the solvent molecules dimensions. Thus, the expansion of the applicable cell potential seems to be the only solution for the significant expansion of the EDLCs specific energy (measured in Wh kg −1 ) and specific power (measured i...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Influence of Iodide Ions Concentration on the Stability of 1-Ethyl-3-methylimidazolium Tetrafluoroborate | Molybdenum Carbide Derived Carbon Electrode Interface

Kruusma

Tõnisoo

Pärna

et al. 2017

J. Electrochem. Soc.

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show abstract

“…[67][68][69][70][71][72] We also exclude studies where the reaction was not carried out in situ, that is, spectra were not recorded while the reaction proceeded, or the sample was moved to a different site in the XPS setup or was even removed from the XPS setup in order to carry out the reaction. [73][74][75][76][77] We also do not address studies that incorporate electrochemical sample manipulation, 66,67,[69][70][71][78][79][80][81][82][83][84][85][86] electrodeposition of metal or organic layers from ILs, [87][88][89][90][91] and IL decomposition 84,[92][93][94][95][96][97][98][99][100][101][102] or nanoparticle formation in ILs. 62,75,103 Each of these topics was studied extensively and would justify a separate review.…”

Section: Introductionmentioning

confidence: 99%

Perspective: Chemical reactions in ionic liquids monitored through the gas (vacuum)/liquid interface

Maier

Niedermaier

Steinrück

2017

The Journal of Chemical Physics

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This perspective analyzes the potential of X-ray photoelectron spectroscopy under ultrahigh vacuum (UHV) conditions to follow chemical reactions in ionic liquids in situ. Traditionally, only reactions occurring on solid surfaces were investigated by X-ray photoelectron spectroscopy (XPS) in situ. This was due to the high vapor pressures of common liquids or solvents, which are not compatible with the required UHV conditions. It was only recently realized that the situation is very different when studying reactions in Ionic Liquids (ILs), which have an inherently low vapor pressure, and first studies have been performed within the last years. Compared to classical spectroscopy techniques used to monitor chemical reactions, the advantage of XPS is that through the analysis of their core levels all relevant elements can be quantified and their chemical state can be analyzed under well-defined (ultraclean) conditions. In this perspective, we cover six very different reactions which occur in the IL, with the IL, or at an IL/support interface, demonstrating the outstanding potential of in situ XPS to gain insights into liquid phase reactions in the near-surface region.

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Unraveling the Capacitive Behaviors in Nanoconfined Ionophilic Carbon Pores

Li,

Cai,

Zhou

et al. 2024

Advanced Materials

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Intensifying the synergy between confined carbon nanopores and ionic liquids (ILs) and a deep comprehension of the ion behavior is required for enhancing the capacitive storage performance. Despite many theoretical insights on the storage mechanism, experimental verification has remained lacking due to the intricate nature of pore texture. Here, a compressed micropore‐rich carbon framework (CMCF) with tailored monolayer and bilayer confinement pores is synthesized, which exhibits a compatible ionophilic interface to accommodate the IL [EMIM][BF4]. By deploying in situ Raman spectroscopy, in situ Fourier‐transform infrared spectroscopy, and solid‐state nuclear magnetic resonance, the effect of the pore textures on ions storage behaviors is elucidated. A voltage‐induced ion gradient filling process in these ionophilic pores is proposed, in which ion exchange and co‐ion desorption dominate the charge storage process. Moreover, it is established that the monolayer confinement of ions enhances the capacity, and bilayer confinement facilitates the charging dynamics. This work may guide the design of nanoconfinement carbon for high‐energy‐density supercapacitors and deepen the understanding of the charge storage mechanism in ionophilic pores.

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Surface chemistry of carbon electrodes in 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid – an in situ infrared study

Cited by 63 publications

References 39 publications

Influence of Iodide Ions Concentration on the Stability of 1-Ethyl-3-methylimidazolium Tetrafluoroborate | Molybdenum Carbide Derived Carbon Electrode Interface

Influence of Iodide Ions Concentration on the Stability of 1-Ethyl-3-methylimidazolium Tetrafluoroborate | Molybdenum Carbide Derived Carbon Electrode Interface

Perspective: Chemical reactions in ionic liquids monitored through the gas (vacuum)/liquid interface

Unraveling the Capacitive Behaviors in Nanoconfined Ionophilic Carbon Pores

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