Bubble-assisted densification of cobalt deposit during electrowinning in CoCl2 solution

Preparation of densified cobalt deposit during electrowinning can enhance the quality of cobalt products effectively for more application. Here we proposed a bubble-assisted electrowinning process in aqueous solution of CoCl2 to achieve the production of high-density cobalt deposit. Electrowinning processes with and without the assistance of a flow of gaseous bubbles was compared by characterizing the microstructure and phase composition of the cobalt deposits. Moreover, electrochemical behavior of cobalt ions was investigated. Upward flowing bubbles can eliminate unsatisfactory influence of dendritic growth and hydrogen evolution on the product, forming compact deposit consisting of fine cobalt crystals. The flowing bubbles are available for preferred growth of cobalt deposit. The current density used in this work and the concentration of CoCl2 can be elevated to an industrial level without the growth of dendritic product. This bubble-assisted method can be employed for the densification of various metals during electrowinning in aqueous solution.