Mechanochemical transformation of spent ternary lithium-ion battery electrode material to perovskite oxides for catalytic CO oxidation†

The recovery of valuable metals from spent ternary lithium-ion batteries (LIBs) has recently garnered significant attention due to the imperatives of the circular economy and environmental management. While the reclamation of lithium is generally straightforward, the hydrometallurgical methods most frequently employed for leaching and separating the remaining nickel, cobalt, and manganese from spent electrode material often yield secondary liquid and solid wastes. In this study, we present a mechanochemical strategy aimed at repurposing lithium-removed spent ternary LIBs cathode material as a precursor for perovskite oxides through a straightforward and scalable solid-state high-energy ball-milling synthesis. By optimizing the synthesis procedure, we have obtained a perovskite catalyst composed of LaNi_0.6Co_0.2Mn_0.2O₃ with a trace amount of phase-separated surface NiO nanocrystals. This catalyst demonstrates outstanding performance in the low-temperature oxidation of CO, exhibiting no degradation in performance over extended periods of service. Notably, it achieves a T₅₀ of 162 °C and a T₉₀ of 197 °C, which compares favorably with previously reported perovskite catalysts prepared via wet synthesis, utilizing fine chemicals as precursors. This approach not only presents a novel method for valorizing spent ternary LIBs but also expands the repertoire of metal precursors available for oxidation catalysts.