Electrochemical behavior of CoCl₂ in ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate

Abstract

The electrochemical behavior of CoCl₂ in 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF₆) was investigated by cyclic voltammetry. The cyclic voltammograms were obtained from electrochemical measurement under different temperatures, and the reversible behavior for Co²⁺/Co³⁺ redox couple on glassy carbon electrode in [bmim]PF₆ was confirmed by the characteristic of the peak currents. The diffusion coefficients (about 10⁻¹¹ m²/s) of Co²⁺ in [bmim]PF₆ under different temperatures were evaluated from the dependence of the peak current density on the potential scan rates in cyclic voltammograms. It is found that the diffusion coefficient increases with increasing temperature. Diffusion activation energy of Co²⁺ in [bmim]PF₆ is also calculated to be 23.4 kJ/mol according to the relationship between diffusion coefficient and temperature.

Keywords

CoCl₂ / electrochemical behavior / ionic liquid / cyclic voltammetry / diffusion coefficient / diffusion activation energy

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