Boosting the sustainable recycling of spent lithium-ion batteries through mechanochemistry

Abstract

The rapid proliferation of spent lithium-ion batteries (LIBs) presents critical challenges to both resource sustainability and environmental sustainability. Conventional recycling methods are often limited by high chemical consumption, complex operations, and poor selectivity. Herein, we report a green and mechanochemically driven strategy for selective recovery of critical metals from mixed LiNi_0.5Co_0.2Mn_0.3O₂ (NCM) and LiFePO₄ (LFP) cathodes. By coupling mechanical activation with the intrinsic redox properties of Fe(II)/Fe(III), the process induces controlled lattice distortion, phase transformation, and spontaneous redox reactions without external reducing agents. Density functional theory (DFT) calculations reveal that mechanochemical activation facilitates the formation of transition metal oxides (MeO, Me = Ni, Co, Mn) and FePO₄, enabling efficient liberation of target metals. Under optimized conditions, 99% Li recovery, >85% Ni, Co, and Mn recovery, and ∼90% Fe and P recovery are achieved using 0.16 M H₂SO₄. This low-energy, low-reagent process simplifies separation, minimizes secondary waste generation, and offers a scalable and sustainable pathway for closed-loop recycling of complex LIB waste, fully aligning with the principles of green chemistry and circular economy.