A plastics-derived organic anode material for practical and sustainable potassium-ion batteries

Organic electrode materials are of particular interest for storing large-size potassium ions. Herein, we demonstrate that polyethylene terephthalate (PET), a synthetic organic polymer with functional carbonyl groups, could deliver a two-electron redox mechanism for potassium storage. The PET particles, synthesized from PET plastic film by a simple solvent thermal method, achieve almost complete utilization of redox-active sites, providing a reversible capacity of 273 mAh/g. Over 800 cycles of cycling life are demonstrated by the PET, along with fast K+-transport kinetics and thus outstanding rate performance. Furthermore, a fabricated full cell composed of PET anode can provide a high operating voltage of 3.17 V with a high energy density of 245 Wh/kg. This study offers a new way to utilize PET plastic waste and guide the development of organic anode for low-cost potassium-ion batteries.