Upcycling Spent LiCoO₂ 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 LiCoO₂ into high-voltage-stable, Mg-doped LiCoO₂ (r-LCO-Mg). Mechanistically, we elucidate that the laser-induced plasma triggers a rapid surface reconstruction, effectively converting the electrochemically inactive rock-salt Co₃O₄ 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.