Electrochemical Behavior of Nickel in the EMIC Ionic Liquid with Glycol

The electrochemistry of Ni(II) was studied with voltammetry and chronoamperometry at glass carbon (GC), mild steel (MS) and Pt electrodes in 1-ethyl-3-methylimidazolium (EMIC) ionic liquid with ethylene glycol. Cyclic voltammetry results shows that Ni(II) could be reduced to nickel metal via a single-step electron transfer process. However, the anodic dissolution of the nickel deposits was sluggish. In addition, the initial reduction potential of Ni(II) shifted positively as the temperature or concentration of Ni(II) increased. The diffusion coefficient of Ni(II) was estimated to be 4.6x10(-7) cm(2) s(-1). The average activation energy for diffusion coefficient is about 21.75 kJ/mol. The electrodeposition of nickel proceeds via three-dimensional instantaneous nucleation with diffusion-controlled growth on both glassy carbon and Pt substrates. Smooth and dense Ni deposits can be obtained from EMIC ionic liquid with glycol.