Recycling LiCoO₂ into Cobalt Metaphosphate for Polyethylene Terephthalate Electro-Reforming to Formic Acid

Spent lithium cobalt oxide (LCO) from retired lithium-ion batteries represents a valuable secondary source of cobalt. Developing efficient catalysts directly from such waste offers an appealing route to simultaneously tackle resource recovery and energy conversion challenges. Herein, a phytic acid-based deep eutectic solvent was applied to selectively extract cobalt from spent LCO, followed by one-step pyrolysis to obtain cobalt metaphosphate (CoPO/C) electrocatalysts. The resulting CoPO/C exhibits remarkable catalytic activity and stability for the electrochemical oxidation of ethylene glycol, enabling its efficient conversion into formic acid under mild conditions. Notably, the superior performance of CoPO/C originates from its strong adsorption capability toward both ethylene glycol and hydroxyl intermediates, which promotes reaction kinetics. This work highlights a sustainable "waste-to-catalyst" strategy that achieves simultaneous resource utilization and green energy production.