Advanced Direct Recycling Technology Enables a Second Life of Spent Lithium-ion Battery

Abstract

With the emergence of the energy crisis and the rise of human environmental awareness, lithium-ion batteries (LIBs), as a new type of energy storage device, are widely used in electric vehicles (EVs), mobile electronic products and stationary energy storage devices. The demand for LIBs has dramatically increased in recent years, leading to a shortage of raw materials for LIBs and a large number of retired LIBs. Therefore, it is particularly important to recycle spent LIBs. Compared with pyrometallurgy and hydrometallurgy, direct recycling, as a more advanced technology, focuses on repairing of the electrodes of spent LIBs. However, direct recycling technology is still in the laboratory operation stage, and there are still many difficulties and challenges to overcome. Herein, we firstly highlight the importance of recycling spent LIBs from LIB market development, raw material supply, environmental impact, and economic benefits. Subsequently, starting from the failure forms and mechanisms of electrode materials, we provide a detailed summary of various direct recycling and upcycling processes, reaction principles, as well as advantages and disadvantages. Additionally, the technology for converting waste cathodes and graphite into new functional materials, a topic rarely addressed in previous reviews, is comprehensively detailed in this review. Lastly, we provide a summary of the current status of LIB recycling and present future challenges. This review may serve as a source of inspiration for researchers and enterprises to develop more advanced recycling methodologies.