Heating- and leaching-free separation of electrodes by liquid metals for regeneration of spent Li-ion batteries

ABSTRACT Efficient separation of aluminum (Al) foil from cathode materials is a key prerequisite for recycling spent Li-ion batteries. Current strategies, relying on thermal treatment or aggressive leaching, suffer from high energy consumption and adverse environmental effects. Here, we present a liquid-metal-induced electrode-separation approach free from heating or leaching. The liquid metal disrupts the passivation layer of the Al and permeates its grain boundaries, enabling the rapid and efficient detachment of active materials. Our combined experimental and computational investigations reveal that the high binding energy between GaSn atoms and the (110) surface of Al drives this grain-boundary diffusion, establishing a foundation for sustainable electrode separation. This approach is universally applicable to widely used cathodes materials, including LiNi1/3Co1/3Mn1/3O2 (NCM), LiCoO2 (LCO), LiFePO4 (LFP) and LiMn2O4 (LMO). The liquid metal can be instantly regenerated by reacting its dissolved Al with H2O, producing high-value H2 as a byproduct without harmful emissions. This process achieves a separation efficiency of ∼99.4% for all electrode materials within 30 minutes, maintaining >99.3% efficiency over repeated cycles and demonstrating outstanding reusability. Crucially, the dissolution of transition metals (Ni, Co, Mn, Fe) is negligible, preserving active material integrity. The regenerated NCM, LCO, LFP and LMO cathodes deliver reversible capacities of 172, 148, 144 and 138 mAh g−1 at 0.1 C, respectively. Techno-economic assessments corroborate that our liquid-metal-enabled separation surpasses conventional methods, providing a green and cost-effective solution for large-scale battery recycling.