Recycling Valuable Metals from Spent Ternary Lithium-Ion Batteries for Low-Temperature NH3-SCR Catalysts: A Pathway for Solid Waste Valorization

Lithium-ion batteries (LIBs) with high energy density and long cycle life are extensively used in electric vehicles, energy storage systems, and other applications, which simultaneously leads to a large number of spent LIBs. Although a large number of spent LIBs pose a serious threat to the environment and human health, timely recovery and disposal of valuable metals in LIBs are crucial for mitigating the scarcity of Li, Ni, and Co resources and reducing environmental hazards in China. This study first disassembled the positive electrode materials of used lithium-ion batteries to obtain ternary powders; then, calcination was carried out under a CO2 atmosphere, and finally lithium was efficiently extracted via hot water leaching. Subsequently, the insoluble residue was leached with nitric acid, and NaOH was added to the resulting mixed metal ion solution to adjust the pH, yielding a Ni-Co-Mn precursor. Finally, a series of NCM/TiO2 catalysts using TiO2 as a support are synthesized via an impregnation method for low-temperature NH3-SCR reactions. The results indicate that the NCM/TiO2 catalysts exhibit optimal catalytic activity over the temperature range of 220–300 °C. Notably, the catalyst with 14 wt% Mn achieves over 85% NO conversion at 220 °C. On the whole, the NCM/TiO2 catalysts can effectively promote the adsorption and activation of NH3 and NO through rich oxygen vacancies and a high density of surface acid sites. This work provides a novel technical pathway and a theoretical foundation for the value-added utilization of spent LIBs.