A hindered-urea vitrimer: recyclable for circular use and upcyclable for rechargeable battery

Abstract

The matter cycle and the renewable energy are fundamental to sustainable development. Despite the recognized urgency of plastic recycling, its implementation is still limited technologically. A dynamic crosslinker can enable a thermoset to exhibit thermoplastic-like reprocessability under elevated conditions, such as elevated temperature or stress, paving the way for plastic recovery, while it retains thermoset properties under normal operational conditions. This study incorporates a hindered urea linkage as the dynamic crosslinker into a commodity plastic to produce a recyclable thermoset. The polymer demonstrates excellent reprocessability under elevated conditions, while maintaining its thermoset characteristics under normal working conditions. Furthermore, considering the inevitability of some eventually-discarded polymer, the upcycling of the polymer waste is demonstrated to produce an advanced carbon for potassium-ion batteries, which are promising for grid-oriented energy storage for green power. With the assistance of zinc oxide during pyrolysis, the polymer-derived carbon showcases excellent performances and cost-effectiveness as anodes in batteries. The dynamic hindered-urea vitrimer thus represents a holistic picture on both recycling and upcycling for circular economy and renewable energy, respectively, towards a sustainable development.