Large-scale direct regeneration of LiFePO 4 @C based on spray drying

Abstract

We present a scalable, cost-effective closed-loop regeneration process of spent LiFePO 4 , including homogenization, spray drying and sintering. The regenerated LiFePO 4 exhibits excellent electrochemical properties. Direct regeneration is a low-cost and environmentally friendly way of recycling spent Li-ion batteries. In this study, a new method is adopted to regenerate spent LiFePO 4 . First, the spent LiFePO 4 powder is homogenized, and then, small amounts of a lithium source and a carbon source are thoroughly mixed by spray drying. After that, a high-temperature solid-phase method is used to regenerate the carbon-coated lithium iron phosphate. Compared with traditional regeneration methods, the proposed method significantly improves the universality of spent LiFePO 4 having different degrees of damage. The regenerated LiFePO 4 is characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and electrochemical measurements. The results show that the regenerated sample has a stable morphology, structure, and electrochemical performance. Under the conditions of 0.1C, the initial capacity exceeds 160 mA h g −1 . After 800 cycles under the conditions of 1C, the capacity retention is 80%, which satisfies the requirements for regenerated LiFePO 4 batteries.