Upcycling Spent LiCoO 2 Via Laser‐Driven Surface Reconstruction: Unraveling the Origin of High‐Voltage Stability

Direct upcycling of spent lithium‐ion batteries (LIBs) is pivotal for sustainable energy storage but remains challenged by the stubborn structural degradation of cathode materials. While conventional recycling involves energy‐intensive destruction and reconstruction of the lattice, we herein report a laser‐assisted direct regeneration (LADR) strategy that upcycles spent LiCoO 2 into high‐voltage‐stable, Mg‐doped LiCoO 2 (r‐LCO‐Mg). Mechanistically, we elucidate that the laser‐induced plasma triggers a rapid surface reconstruction, effectively converting the electrochemically inactive rock‐salt Co 3 O 4 phase back into a layered CoOOH intermediate, thereby lowering the barrier for Li + re‐intercalation and defect remediation. Concurrently, Mg doping fortifies the bulk oxygen framework, suppressing deleterious oxygen release and cobalt dissolution at high cut‐off voltages (4.6 V). Advanced characterization coupled with theoretical calculations reveals that this synergistic surface‐bulk engineering repairs atomic‐level defects and accelerates Li + diffusivity. Consequently, the r‐LCO‐Mg cathode delivers exceptional electrochemical stability, retaining 96.7% capacity after 100 cycles at 4.6 V (0°C) and demonstrating robust practicality in pouch cells (81.7% retention after 400 cycles). Techno‐economic analysis further underscores the scalability of LADR, establishing it as a transformative, chemically efficient pathway for closing the loop on critical battery materials.