A Low-Energy and Waste-Minimized Recycling Strategy for Lithium-Ion Batteries: Mechanistic Study and Industrial Potential

The rapid growth of lithium-ion batteries (LIBs) in electric vehicles, energy storage systems, and electronics has intensified the need for sustainable waste management and critical-metal recovery. This study establishes a low-energy, environmentally benign aqueous recycling process that directly treats unsorted black mass and upgrades recovered products to battery-grade precursors. An absolute chemical precipitation route combining optimized leaching conditions (3.5 M H2SO4, 8 vol% H2O2, 70 °C, 1 h, 20 g L−1 pulp density) with sequential pH-controlled precipitation effectively recovers FePO4, Al(OH)3, MnO2, Co2O3·3H2O, Ni(OH)2, and Li2CO3, achieving > 90 % leaching and recovery for LCO, NMC, NCA, LFP, and LMO cathodes. Pilot-scale operation (5 kg day−1) produced > 90 %-pure products, near-zero wastewater through Na2SO4 recycling, and an estimated profit of ≈ US $1,900 per batch. Further purification via mild-acid leaching (pH 0, 2 h, 20 g L−1) and Na2SO4 crystallization raised Co2O3·3H2O and Li2CO3 purities to > 99.5 wt % with only 2.2 wt % Co loss. For LiFePO4 cathodes, a CaCl2-assisted roasting step (600 °C, 1 h) decomposes PVDF, converts LiFePO4 to water-soluble LiCl (99.8 % leaching), and immobilizes F as fluorapatite, yielding 99.8 %-pure Li2CO3 and suppressing HF release. Reaction mechanisms and products were verified by XRD, XPS, SEM–EDS, and TG– DSC, while DFT and CALPHAD modeling confirmed thermodynamic feasibility. Overall, this fully aqueous, waste-minimized process offers high efficiency, environmental safety, and industrial potential for circular LIB recycling.