Upcycling Spent Graphite Anodes into Bifunctional Photothermal Catalysts for Efficient PET Chemical Recycling

The economic recovery of anodes in lithium-ion batteries remains challenging due to their low value. Here, the study presents a cross-sector battery-plastic co-upcycling strategy that transforms spent graphite anodes into bifunctional photothermal catalysts for efficient Polyethylene terephthalate (PET) depolymerization. Upon reaction with ethylene glycol (EG), lithiated graphite spontaneously enables copper foil detachment, graphite regeneration, and in situ formation of organolithium species (C₂H₄O₂Li_2-xH_x). The resulting catalyst system achieves 95% PET conversion and 64.6% BHET yield within 15 minutes under 0.71 W/cm² sunlight. Mechanistically, a synergistic effect between solid electrolyte interphase (SEI)-derived Li₂CO₃/Li₂O and organolithium intermediates significantly accelerates glycolysis. Techno-economic modeling for a 90 000 ton/year facility reveals a minimum selling price of $0.956/kg for BHET and annual energy savings of 5.039 × 10¹¹ kJ. This work highlights a scalable, low-cost approach to integrate battery and plastic waste recycling, offering a new paradigm for sustainable urban mining and circular polymer economy.