- Related item:
- Investigating the Electrode Kinetics of the Li/Li+ Couple in a Wide Range of Room Temperature Ionic Liquids at 298 K
- Description:
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Cyclic voltammetry experiments are carried out using a 0.1 M Li+ solution in 12 different room temperature ionic liquids (RTILs), [C4mpyrr][NTf2], [C4dmim][NTf2], [N2,1,1,3][NTf2], [N6,2,2,2][NTf2], [C4mim][OTf], [C4mpyrr][N(CN)2], [C2mim][NTf2], [P14,6,6,6][FAP], [C4py][NTf2], [C4mim][PF6], [C4mim][NTf2], and [N1,8,8,8][OTf], on a Ni microelectrode to investigate the deposition and stripping of lithium from the electrode surface. [C4mpyrr][N(CN)2], [C2mim][NTf2], [P14,6,6,6][FAP], [C4py][NTf2], [C4mim][PF6], [C4mim][NTf2], and [N1,8,8,8][OTf] did not have a wide enough potential window to observe the deposition and stripping of bulk lithium. In the experimental data recorded for [C4mpyrr][NTf2], [C4dmim][NTf2], [N2,1,1,3][NTf2], [N6,2,2,2][NTf2], and [C4mim][OTf], a single stripping peak for bulk lithium is seen, and kinetic data for the Li/Li+ couple are extracted by comparison with computational simulations. The electrochemical rate constant, k0, is found to have values ranging from (1.3·10−6 to 1.2·10−5) cm·s−1. Diffusion coefficients for the Li+ ion in these five RTILs are also reported.
- Related item:
- The electrode potentials of the Group I alkali metals in the ionic liquid N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide
- Description:
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The redox couples M/M+ of the Group I alkali metals Lithium, Sodium, Potassium, Rubidium and Caesium have been extensively investigated in a room temperature ionic liquid (IL) and compared for the first time. Cyclic voltammetric experiments in the IL N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C4mpyrr][NTf2]) and subsequent simulation of the data has allowed the determination of the formal potential ( vs. ferrocene/ferrocenium), standard electrochemical rate constant (k0) and transfer coefficient (α) for each couple in the group. The trend in in [C4mpyrr][NTf2] is remarkably similar to the established trend in the common battery electrolyte, propylene carbonate.
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- In situ electrochemical-X-ray Photoelectron Spectroscopy: Rubidium metal deposition from an ionic liquid in competition with solvent breakdown
- Description:
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The electrodeposition of rubidium from an ionic liquid (IL) N-butyl-N-methylpyrrolidium bis(trifluoromethylsulfonyl)imide ([C4mpyrr][NTf2]) has been performed and monitored at a Nickel mesh electrode by using in situ electrochemical-X-ray Photoelectron Spectroscopy (XPS) measurements. At extremely high current values during the deposition of the metal, the solvent breakdown was also observed. By choosing suitable low current values, electrodeposition of Rb can be promoted over the IL degradation. IL degradation was characterised by carbonisation of the electrode-IL-vacuum interface, with the loss of fluorine being relatively pronounced, consistent with reduction of the [NTf2]− anion.
- Related item:
- Monitoring potassium metal electrodeposition from an ionic liquid using in situ electrochemical-X-ray photoelectron spectroscopy
- Description:
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The real time electrodeposition of potassium has been monitored for the first time in an ionic liquid using in situ electrodeposition-X-ray photoelectron spectroscopy (XPS). The ionic liquid used was N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C4mpyrr][NTf2]), and electrodeposition occurred at a nickel mesh electrode. Potassium electrochemistry was monitored at the ionic liquid–vacuum–electrode interface using a novel cell design.
- Related item:
- A Study of the Na/Na+ Redox Couple in Some Room Temperature Ionic Liquids
- Description:
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Cyclic voltammetry experiments were conducted using solutions of Na+ ions in 12 different ionic liquids (RTILs) on a nickel microelectrode in order to observe the deposition and stripping of metallic sodium. In most of the liquids the potential window was insufficient to observe the formation and removal of bulk sodium, despite the enlargement of some potential windows in the presence of sodium. However, in the ionic liquids N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C4mpyrr][NTf2]), N-ethyldimethylpropylammonium bis(trifluoromethylsulfonyl)imide ([N2,1,1,3][NTf2]) and N-hexyltriethylammonium bis(trifluoromethylsulfonyl)imide ([N6,2,2,2][NTf2]) the deposition and stripping peaks for the bulk sodium were observed, allowing simulation of the current−voltage curves and extraction of kinetic and thermodynamic data, notably the electrochemical rate constant, k0, and the formal potential, Ef0, for the Na/Na+ couple. Variable temperature measurements also gave quantitative information on the temperature dependence of Ef0, dEf0/dT. Diffusion coefficients for Na+ ions in the three RTILs are also reported. All parameters are compared and contrasted with that of the Li/Li+ couple, demonstrating that sodium possesses a more positive Ef0 than lithium in the investigated RTILs, although the difference is markedly less than that in solvents such as water or ammonia.
- Related item:
- Kinetic and Thermodynamic Parameters of the Li/Li+ Couple in the Room Temperature Ionic Liquid N-Butyl-N-methylpyrrolidinium Bis(trifluoromethylsulfonyl) Imide in the Temperature Range 298−318 K: A Theoretical and Experimental Study Using Pt and Ni Electrodes
- Description:
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The Li/Li+ couple is investigated in the room temperature ionic liquid N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, [C4mpyrr][NTf2], at a range of temperatures varying from 298 to 318 K. Experiments are conducted using both nickel and platinum microelectrodes. On nickel, a single stripping peak is observed for the stripping of bulk lithium that allowed thermodynamic and kinetic parameters to be extracted via computational simulation. At 298 K, the electrochemical rate constant (k0) = 1.2 × 10−5 cm s−1, the diffusion coefficient (D) = 4.5 × 10−8 cm2 s−1, the formal potential (Ef0) = −3.26 V versus the Fc/Fc+ reference couple, and the transfer coefficient (α) = 0.63. On platinum, multiple stripping peaks are observed due to the stripping of Li−Pt alloys in addition to the stripping of bulk lithium. The ratio of the different stripping peaks is found to change with temperature, indicating that Li−Pt alloys are more thermodynamically stable than pure bulk lithium and platinum.
