Study on the Behavior of Electrochemical Extraction of Cobalt from Spent Lithium Cobalt Oxide Cathode Materials

The molten salt electrochemical method was used to reduce the Co in spent LiCoO(2). The reduction mechanism of Co (III) in LiCoO(2) was analyzed by cyclic voltammetry, square wave voltammetry, and open circuit potential. The reduction process of Co (III) on Fe electrode was studied in NaCl-CaCl(2)-LiCoO(2) molten salt system at 750 °C. The results show that the reduction process of Co (III) is a two-step reduction: Co (III) → Co (II) → Co (0) and they are all quasi-reversible processes controlled by diffusion. Phase analysis (XRD) shows that Li(+) and Cl(2−) in the molten salt form LiCl electrolysis experiments with different voltages were carried out, which proved the stepwise reduction of Co in LiCoO(2).