Boosting tenfold recycling profit by a one-step calcination strategy for upcycling spent LiCoO2 to high-value Li6CoO4

Abstract

Lithium cobalt oxide (LiCoO₂) consumes 40% of the global cobalt reserves annually. However, the low profitability of current recycling methods results in extremely low cobalt recovery rates that seriously threaten the sustainability of cobalt resources. Here, we developed an upcycling strategy that regenerates the spent LiCoO₂ to high-value Li₆CoO₄, offering a profit increase of 7–13 times compared with that of the existing recycling technologies. Moreover, the regeneration mechanism and structural evolution were systematically investigated. Benefiting from the naturally endowed carbon coating layer formed during the one-step calcination strategy, the reconstructed Li₆CoO₄ delivered an irreversible capacity of 850 mAh g⁻¹ when used as a Li⁺ supplement synergist in lithium-ion batteries, outperforming the commercial Li₅FeO₄ counterparts by offering 40% performance improvement. Besides, it showed extraordinary air stability, retaining 96% of the capacity after 24 hours of exposure to the atmosphere. This research proposes a sustainable strategy to tackle the global challenges of cobalt recycling and supply shortages.