Interfacial process engineering of a co-grinding agent for recycling spent lithium-ion batteries

Abstract

In the field of new-energy systems, the use of spent lithium-ion batteries is being rationalized as a prospective industry. However, with the progress of technology, the exploration of strategies that are efficient, green, and energy-saving has become the major issue for recycling batteries. Recently, the mechanochemical activation (MCA) process has been proposed as a method for reducing leaching time and temperature, further tackling the excessive usage of corrosive chemical agents in hydrometallurgical techniques. Herein, we present a co-grinding agent of spent LiCoO₂ (S-LCO) and Na₂SO₃ (reduction properties) to facilitate the physical and chemical transformations of the S-LCO, thereby enhancing the leaching process. MCA can refine particle size, enhance its hydrophilicity, induce lattice distortion and refine lattice structure, and thereby the surface energy and surface negative charge are increased, further improving the reaction activity of S-LCO. Meanwhile, Na₂SO₃ promotes the isomorphic substitution between Na⁺ and Li⁺ and reduces Co³⁺ to Co²⁺. Because of this superiority, this novel MCA shortens leaching time and reduces leaching temperature, as well as improves leaching efficiency and reduces the use of acidic solvents. Practically, the cell with regenerated LiCoO₂ exhibits excellent cycling performance and rate capability (a high capacity retention of 84.54% after 120 cycles at 0.2 C), which sheds some light on the interface process engineering of a co-grinding agent for recycling spent lithium-ion batteries.