Reductive leaching of cathodic active materials from lithium ion battery wastes

Reductive leaching of LiCoO2 from spent lithium ion battery was investigated in terms of reaction variables. The leaching efficiency of LiCoO2 increased with increasing temperature, and concentration of HNO3, but with decreasing solid/liquid (S/L) ratio. Li and Co from LiCoO2 were leached over 95% with the addition of 1.7 vol.% H2O2 as a reducing agent. This is due to the reduction of Co3+ to Co2+ which can be readily dissolved. The dissolution rates of Co and Li were inversely proportional to their respective concentrations in the solution. Apparent activation energies of 12.5 and 11.4 kcal/mol were obtained for Co and Li, respectively. This indicates that the dissolution of LiCoO2 is controlled by surface chemical reaction.