Upcycling plastic waste to carbon materials for electrochemical energy storage and conversion

Plastic pollution is triggering a global environmental crisis, prompting incremental efforts in recycling and upcycling to unlock the hidden value. Converting plastic waste into value-added carbon-based materials provides attractive options for electrochemical energy applications. This review initially summarizes the available plastic waste feedstock concerning the contained elements for carbon-based materials. Then, the transformation process of plastics into carbon-based electrode materials including carbon quantum dots, carbon nanospheres, carbon nanosheets, carbon nanotubes, 3D porous carbon, and carbon-based composites, and their electrochemical applications based on structural characteristics are comprehensively reviewed. In this part, the superiority and drawbacks of different plastics-to-carbon transformation systems, and the relationships between dimensional carbon structures and electrocatalytic performances for energy storage and conversion are discussed. Finally, existing challenges and outlook of controllable upcycling of plastic waste into carbonous materials for electrochemical applications are presented. This review provides inspiration on the exploration of advanced techniques for upgrading discarded plastics for energy applications, and forward-looking ideas for achieving sustainability and profitability in the plastics value chain management.