Molten salt upcycling of waste PET into high-performance lithium-ion battery anodes

The widespread use of polyethylene terephthalate (PET) poses serious environmental challenges, while conventional mechanical reprocessing or pyrolysis methods remain inefficient and yield low-value products. Here we present a molten salt-mediated pyrolysis strategy for upcycling waste PET into high-performance anodes for lithium-ion battery. PET is depolymerized in a zinc-containing molten salt to form a metal-organic framework intermediate, which is then carbonized at high temperature to produce porous carbon nanosheets. The molten salt serves simultaneously as a heat-transfer medium and structural template, promoting uniform carbonization, preventing framework collapse, and enhancing graphitization. The resulting carbon as a lithium-ion battery anode exhibits a reversible capacity of 600 mAh g −1 at 0.1 A g −1 and retains 93% of its capacity after 1000 cycles at 0.5 A g −1 . The full cell incorporating LiFePO 4 cathode demonstrates stable cycling over 600 cycles with negligible capacity degradation.