Efficient Regeneration of Spent Lithium Iron Phosphate Cathodes Materials via Oxidation-Reduction for Industrial-Scale Recycling

Recycling spent lithium iron phosphate (LFP) batteries is crucial for resource conservation and environmental sustainability. However, the heterogeneous nature of spent LFP materials presents challenges for universal recycling solutions. This work proposes an oxidation-reduction process to regenerate LFP cathode materials, reconstructing their lattice structure through high-energy sanding and spray drying. The regenerated LFP exhibits uniform elemental distribution, regular spherical morphology, and excellent electrochemical performance. The initial capacity is 144.9 mAh g⁻¹ at 1C with 98% capacity retention after 400 cycles. Additionally, the material maintains an initial capacity of 135.4 mAh g⁻¹ at 2C, with 97% capacity retention after 400 cycles. Density functional theory (DFT) calculations confirm that removing Fe²⁺ defects enhances Li⁺ diffusion, improving electrochemical performance. Compared to traditional hydrometallurgical and pyrometallurgical recycling methods, the oxidation-reduction process is low-cost, less polluting, and offers a profit of 2.45 $ kg⁻¹. This method enables large-scale, homogeneous recycling of spent LFP materials while maintaining high electrochemical performance. This work not only provides an in-depth study of the lattice reconstruction of LFP materials but also provides a novel strategy for homogeneous recycling on an industrial scale.