Direct regeneration of cathodes from spent LIB black mass through an integrated roasting-flotation method with impurity-tailored self-decontamination

Abstract

To address the critical incompatibility between direct recovery technology and industrial battery-crushing technology, this work proposes a short-process, eco-friendly strategy for the direct regeneration of cathode materials from spent lithium-ion battery black mass (BM). In this strategy, the cathode material (designated S-NCM) with a 99.08% recovery and a 95.92% grade is first extracted greenly and nondestructively via flotation separation after roasting pretreatment. Crucially, the residual metal impurities in BM are ingeniously utilized to capture fluorinated pollutants (e.g., HF) during the roasting process, effectively eliminating hazardous gas emissions. Following targeted prelithiation and high temperature sintering, S-NCM is transformed into a regenerated cathode material (R-NCM). Electrochemical tests demonstrate that R-NCM delivers a reversible specific capacity of 139.27 mAh g⁻¹ at 0.1C and maintains 91.85% capacity retention after 100 cycles. Techno-economic analysis confirms the strategy's significant environmental benefits and commercial viability. The total energy consumption of direct regeneration (2.88 MJ kg⁻¹) is substantially lower than that of pyro-methods (39.12 MJ kg⁻¹) and hydro-methods (42.97 MJ kg⁻¹). Owing to its simplicity, low energy demand, and elimination of secondary synthesis, the regenerated cathode material can be directly used for battery remanufacturing. Consequently, the direct regeneration strategy offers 6.8- and 2.4-fold higher profitability than pyro- and hydro-methods, respectively. This study provides a sustainable solution for the large-scale direct regeneration of spent battery-derived BM.