Cobalt Electrodeposition from Cobalt Chloride Using Urea and Choline Chloride Ionic Liquid: Effect of Temperature, Applied Voltage, and Cobalt Chloride Concentration on Current Efficiency and Energy Consumption

摘要

Electrodeposition of cobalt from cobalt chloride using the urea and the choline chloride ionic liquid (2:1 molar ratio) was studied to search the optimized parameters for the higher current efficiency. The cyclic voltammetry was tested with 0.2 M CoCl_2 using various scan rates to determine the reduction potential in Urea/ChCl at 323 K. Based on the data from cyclic voltammetry test, the transfer coefficient and the diffusion coefficient were calculated as 0.22 and 3.38 × 10~(-6) cm~2/s, respectively. The parameters for electrodeposition of cobalt were various temperatures (323-383 K), applied potentials (2.4-3.3 V), and concentration of CoCl_2 (0.2-0.5 mol/L). Current efficiency and energy consumption were calculated to investigate the optimal condition for the electrodeposition of cobalt. The highest current efficiency (95%) was obtained under the temperature 323 K, the applied voltage 2.7 V, and concentration 0.5 mol/L of CoCl_2. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were used for the characterization of cobalt deposits.