Efficient reduction of spent cathode materials via in-situ thermal reduction by defect-rich petroleum coke

Based on the dual attributes of environmental risk and resource value of spent Lithium-ion batteries (LIBs), low-cost and high-efficiency recovery methods of valuable metals from spent LIBs have been widely studied. Here, a strategy to efficiently recover valuable metals from spent cathode materials using defect-rich petroleum coke (PC) is proposed. The results show that only 5.8% PC is required to reduce the spent cathode materials at 700°C for 60 min, which shows strong reducibility. Meanwhile, thermodynamic and DFT calculations explore the mechanism of strong reducibility of defect-rich PC in the recovery of spent cathode materials. Based on the strong reduction effect of PC and the synergistic effect of gas-solid reaction and solid-solid reaction, the spent cathode materials are converted to soluble Li2CO3 as well as insoluble Ni, Co and MnO. The CO2 produced in the PC-assisted roasting process can participate in the Boudoureau reaction and the formation of Li2CO3 in situ, accelerating the efficient reduction of spent cathode materials and realizing the high value-added utilization of the roasting byproducts—CO2. The regenerated cathode materials show excellent electrochemical properties. This closed‐loop recovery process uses PC instead of expensive graphite, with a profit of around 6.67 $∙kg-1 cell, which reduces the cost.