Synthesis, characterization and catalytic properties of cobalt oxide recovered from spent lithium-ion batteries

Abstract

Cobalt oxide was synthesized after a biohydrometallurgical process to recycle lithium-ion batteries (LIBs) from laptops. After separating the components of the spent LIBs, the cathodic material was leached with a biogenerated sulfuric acid at room temperature. Using 5% v/v H2O2 at 2 h, 60% Co was solubilized. After three successive lixiviation steps, 95% cobalt was solubilized. A cobalt oxide (CoOx-R) was obtained by precipitation with H2C2O4 and calcination at 500 °C, and was compared to both a cobalt oxide synthesized in the same way but using a commercial cobalt salt (CoOx) and the cathodic material before leaching (LiCo). The characterization by XRD, FTIR, XPS and TPR demonstrated the presence of Co3O4 in CoOx and CoOx-R and LiCoO2 phase in LiCo sample. CoOx and CoOx-R are better catalysts for VOC oxidation than LiCo due to higher SBET and the presence of the Co3O4. CoOx has a lower temperature for ethanol total oxidation but CoOx-R produces less acetaldehyde than CoOx. On the other hand, in toluene oxidation CoOx and CoOx-R present a similar performance, with a complete conversion near 300 °C. Cobalt oxide obtained using spent LIBs batteries as raw materials could be used as catalysts for VOC removal.