A green strategy for the selective recovery of lithium and the synthesis of CoFe2O4 catalyst for CO oxidation from spent lithium-ion batteries

Abstract

Spent lithium-ion batteries (LIBs) are an essential secondary resource containing valuable metal elements. The recovery of valuable metals from spent LIBs poses immense importance in terms of environmental protection and mitigating resource shortages. Sulfation roasting has been demonstrated to have high efficiency in recovering valuable elements from spent LIBs. Nevertheless, conventional sulfation roasting techniques have certain drawbacks, such as lack of sustainability and an adverse environmental impact, due to the utilization of costly sulfation reagents and the emission of SO₂. Herein, a green strategy involving waste copperas-assisted sulfation and roasting–water leaching process with SO₂-free emissions is proposed to selectively recover lithium and prepare low-cost LIB-derived CoFe₂O₄ catalysts from spent lithium cobalt oxide (LCO) batteries. Under optimal conditions, approximately 92.87% of lithium in the LCO battery cathode could be successfully recovered as Li₂CO₃ with a purity of 99.69%. Additionally, the prepared LIB-derived CoFe₂O₄ catalyst showed an excellent CO catalytic activity at 300 °C, with about 98% of CO being effectively oxidized. The catalysis process followed a Mars–van Krevelen-type mechanism, where CO was oxidized by the interaction with the adsorbed oxygen species and lattice oxygen. This strategy is the first to combine the selective recovery of lithium with CO purification, achieving the efficient and functional utilization of spent LIBs and providing a new strategy for treating spent LIBs.