Electrochemical recycling of cobalt from spent cathodes of lithium–ion batteries: its application as coating on SOFC interconnects

In this work the metallic cobalt was electrodeposited on 430 steel in order to obtain a low electrical resistance film made to Co 3 O 4 . Pure cobalt was obtained by acidic dissolution of lithium cobalt oxide (LiCoO 2 ) present in exhausted Li-ion battery cathode. The electrodeposition was performed with a 96% efficiency at a potential of 1.50 V versus Ag/AgCl. The electrodeposited cobalt showed the face-centered cubic (23%) and hexagonal centered (77%) phases. After oxidation at 850 °C for 1000 h in air, the cobalt layer was transformed into the Co 3 O 4 phase. On the other hand, a sample without cobalt showed the usual Cr 2 O 3 and FeCr 2 O 4 phases. After 1000 h at 850 °C, in air the area specific resistance of the sample with the cobalt oxide layer was 0.038 Ω cm −2 , while it was 1.30 Ω cm −2 for the bare sample.