Recycling Spent Lithium‐Ion Layered Cathodes: Toward Direct Single‐Crystalline Regeneration Technology

Direct single‐crystalline regeneration (DSCR) techniques of layered cathodes in lithium‐ion batteries have attracted considerable research attention. Nonetheless, current development and commercial application of DSCR techniques remain constrained by different failure conditions of cathode materials, the complexity of production processes, and the opacity of evaluation systems. Herein, recent works on DSCR techniques applied to spent layered cathodes are summarized and compared. First, the failure mechanism of LiCoO 2 (LCO) and Ni‐based cathodes (NCM and NCA) is discussed, followed by a critical assessment of the current advantages and challenges of single‐crystalline cathodes. Considering the different Li supplement and Ni contents, the electrochemical performance for the reported regenerated of LCO, Ni‐lean, Ni‐medium, and Ni‐rich cathodes is separately studied and compared. Based on comprehensive evaluation and comparison, a multi‐dimensional feasibility and strategy analysis for the development direction of targeted single‐crystalline products and manufacturing techniques is provided. Finally, a prospect for future developments and challenges for the DSCR processes is further provided, with the hope of inspiring further advances toward the green and sustainable regeneration of spent lithium‐ion batteries.