Beneficiation-free direct lithium recovery from graphite/LFP-dominant industrial lithium-ion battery waste containing NCM and Cu/Al foils

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Conventional selective lithium recovery from spent lithium-ion batteries (LIBs) generally relies on beneficiation or physical separation processes to obtain relatively purified black mass or cathode materials prior to leaching. In this study, a beneficiation-free and acid-emission-free strategy was developed for direct selective lithium extraction from industrial mixed LIB waste containing lithium iron phosphate (LFP), graphite, copper/aluminum foil, and minor cross-contaminated lithium nickel cobalt manganese oxide (NCM) components. Unlike conventional processes requiring extensive physical separation, the proposed HCOOH–H 2 O 2 system enables selective lithium leaching while effectively suppressing impurity metal dissolution in a highly heterogeneous industrial waste matrix. To systematically optimize the leaching process, orthogonal experiment design, response surface methodology, and regression modeling were integrated to investigate the coupled effects of HCOOH concentration, H 2 O 2 concentration, and liquid-to-solid ratio (L/S) on lithium recovery and leaching selectivity. Under the optimized conditions, the lithium leaching efficiency reached 99.39 ± 0.58%, while the leaching efficiencies of Fe, Al, Co, Cu, Mn, and Ni were controlled at 0.09 ± 0.02%, 0.14 ± 0.07%, 0.50 ± 0.16%, 0.14 ± 0.03%, 0.91 ± 0.06%, and 0.74 ± 0.08%, respectively. The post-leaching solution remained near-neutral, thereby preventing the formation of acidic wastewater. In addition, the developed modeling strategy enabled the identification of a balanced operational window between high lithium recovery and impurity suppression, which would be difficult to accurately determine using conventional one-factor-at-a-time experimental optimization approach. This study demonstrates the feasibility of direct selective lithium recovery from realistic industrial mixed LIB waste without beneficiation and provides new insights into simplified and more sustainable recycling strategies for complex spent LIBs. By eliminating conventional beneficiation and physical separation operations, the proposed strategy has the potential to reduce process complexity, energy consumption, equipment requirements, and associated environmental burdens during industrial LIB recycling.