Selective Lithium Leaching from Heterogeneous Industrial LIBs Waste: Quantifying Coupling Leaching Effects in LiFePO ₄ ‐Dominant Systems Containing Graphite and Metallic Foils

ABSTRACT With the rapid increase in spent lithium‐ion battery generation, the selective recovery of lithium from complex mixed battery wastes has become a critical challenge in resource recycling. However, conventional single factor optimization cannot adequately capture the coupled effects of leaching factors in governing leaching behavior and selectivity to achieve the high lithium extraction and minimal impurity dissolution. In this paper, the Box–Behnken response surface methodology (RSM) was used in a nitric acid–hydrogen peroxide (HNO ₃ –H ₂ O ₂ ) system for lithium extraction from industrial black mass containing LFP, minor NCM, graphite, and metallic foils (Cu/Al). By construct a two‐factor interaction linear regression model, Li and Fe leaching efficiencies and pH after leaching were statistically analyzed and the optimum conditions was confirmed. Under the optimum conditions of 0.60 mol/L HNO ₃ , 4.80 vol% H ₂ O ₂ , and 10.34 mL/g, the leaching rate of Li reached 99.50% whereas Fe dissolution remained as low as 0.74%. Further analysis indicates that the Fe–P framework was remained and minor ternary components was decomposed during the lithium leaching process. Unlike conventional studies focusing on homogeneous cathode materials, by using RSM, this work quantifies the coupling leaching interactions for industrial black and provides a robust process window mass for both mechanistic insight and a quantitative basis for low‐temperature, short‐process, highly selective lithium recovery.