Conductivity and Dissociation Constants of Quaternary Ammonium Perchlorates and Picrates in 4-Methyl-pentan-2-one

Goga, Sergey T.; Lebed, Alexander V.; Mchedlov‐Petrossyan, Nikolay O.

doi:10.1021/je9008969

Cited by 6 publications

(2 citation statements)

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Section: Methodsmentioning

confidence: 52%

“…The specific resistivity of the remaining quaternary ammoniums used in this study is expected to be close to the specific resistivity of NBu 4 I, as it was shown that the chain length of substituents (ethyl to hexyl) and the symmetry of quaternary ammonium salts changes the specific conductivity by less than 10%. [29][30][31] The IR drop across the working and reference electrodes at current densities of 1 to 5 mA/cm 2 is less than 1 mV in this study. (I R = J A (ρ L/A) = J ρ L = 5 mA cm −2 × 0.071 cm × 0.5 cm < 1 mV, where A is the area of the working electrode, L is the distance between the reference and working electrodes, ρ is the specific resistivity of the solution, and R is the solution resistance.…”

Section: Methodsmentioning

confidence: 60%

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Electrochemical Stability of Quaternary Ammonium Cations: An Experimental and Computational Study

Mousavi

Kashefolgheta

Stein

et al. 2015

J. Electrochem. Soc.

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Quaternary ammonium ions, NR 4 + , are among the most electrochemically stable organic cations. Because of their wide electrochemical windows, they are frequently used in batteries and electrochemical capacitors. Improving the electrochemical stability and expanding the electrochemical windows of quaternary ammonium ion is highly desired. In this work, we investigated the electrochemical stability of quaternary ammonium ions and showed that the chain length, type (primary vs. secondary), size, and steric hindrance of the saturated alkyl substituents have only a very small effect (less than 150 mV) on their electrochemical stability toward reduction. To provide a molecular understanding of substituent effects on electrochemical stability, quantum calculations were performed employing density functional theory, and it was shown that the structure of saturated aliphatic alkyl substituents has only minimal effects on the electronic environment around the positive nitrogen center and the LUMO energy level of quaternary ammonium cations. Moreover, a linear correlation between the cathodic limit and the LUMO energy levels of the NR 4 + , N-butylpyridinium, and 1-ethyl-3-methylimidazolium ions was found, suggesting that electrochemical stabilities of new cations may be computationally predicted on the basis of LUMO energies of these systems. With the increasing global demand for energy, improving existing energy storage technologies is as critical as developing more efficient methods for energy production. For one important class of energy storage technologies, namely electrical energy storage, the energy density of a device is usually limited by the voltage window in which the device can function. Therefore, expanding the working voltage range of such devices is highly desired. The electrochemical decomposition of electrolytes, which are commonly used in energy storage devices such as electrochemical capacitors, often limits the useful voltage window 1 because these devices can function properly only within the electrochemical window of their electrolyte. Modifying the structure of electrolytes and improving their electrochemical stabilities has been the focus of numerous studies to date. [2][3][4][5][6][7][8][9][10][11][12][13][14][15] The electrochemical window of an electrolyte is the voltage range in which the electrolyte is chemically stable and does not get reduced or oxidized as a result of the applied potential. 16 The upper end of the electrochemical window is usually limited by the oxidation of the anion, and the lower end of the electrochemical window is determined by the reduction of the cation. 1 One of the most electrochemically stable classes of organic cations comprises the quaternary ammonium ions, NR 4 + . These are highly inert toward reduction, offer wide electrochemical windows, and are, therefore, frequently used in batteries and capacitors. 2,5,6,17 Much research has been devoted to improving the electrochemical stability of quaternary ammonium ions. 4,[9][10][11][12][13][14][15] Reduction of qua...

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Section: Methodsmentioning

confidence: 52%

Section: Methodsmentioning

confidence: 60%