Pyrolytic reduction roasting of used ternary lithium-ion battery cathode powder using coconut shell powder for selective recovery of lithium

Abstract

Abstract

Extensive attention is being devoted to the issues of environmental pollution and resource scarcity, which has prompted heightened interest in the recycling of spent lithium-ion batteries. In this paper, coconut shells, commonly considered as waste, were used as reducing agents for the recovery of valuable metals from spent lithium-ion battery powder (LiNi0.6Co0.2Mn0.2O2) though biomass-assisted pyrolysis, with the aim of alleviating lithium resource scarcity and addressing the environmental problems associated with the disposal of large quantities of spent batteries. During pyrolysis reduction process, the LiNi0.6Co0.2Mn0.2O2 (S-NCM) was first decomposed to dissociate into Li0.14Co0.86O, (NiO)0.75(MnO)0.25, Ni6MnO8 and Li2CO3, and then gradually reduced to Ni, Co and MnO. The reaction kinetics demonstrated that the apparent activation energies (Ea) ranged from 20 to 40 kJ∙mol−1, indicating that the reduction process was supervised by chemical reactions. To analyze the experimental outcomes and elucidate the mechanism of pyrolytic reduction, analytical techniques including TG-DTG-DSC, FT-IR, XRD, SEM, XPS, and TG-MS were utilized. Following pyrolytic reduction, the leaching efficiency of Li from the S-NCM through water leaching was 96.03 %. This method not only facilitates the effective recovery of lithium from the S-NCM without adding chemical reagents, but also enables the resourceful use of spent coconut shells, and addresses substantial environmental challenges. This study presents an efficient, cost-effective, and environmentally friendly process for the recovery of valuable components from the S-NCM.