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

Abstract Efficient separation of Al foil from cathodes is a 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 of heating or leaching. The liquid metal disrupts Al’s passivation layer and permeates its grain boundaries, enabling rapid and efficient detachment of active materials. Our combined experimental and computational modeling reveals that the strong binding energy between GaSn atoms and Al’s (110) surface drives this grain boundary diffusion, establishing a foundation for sustainable separation. This approach is a universal methodology for all widely used cathodes, including LiNi1/3Co1/3Mn1/3O2 (NCM), LiCoO2 (LCO), LiFePO4 (LFP), and LiMn2O4 (LMO). The liquid metal can be instantly regenerated by reacting with H2O to remove dissolved Al, 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% over repeated cycles, demonstrating outstanding reusability. Crucially, 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, eco-friendly, and cost-effective solution for large-scale battery recycling.