Large-scale direct regeneration of LiFePO4@C based on spray drying†

Abstract

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 LiFePO₄. First, the spent LiFePO₄ 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 LiFePO₄ having different degrees of damage. The regenerated LiFePO₄ 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 LiFePO₄ batteries.

Keywords: LiFePO₄; Direct regeneration; Homogenization; Spray drying; Electrochemical performance.