Converting waste poly(ethylene terephthalate) into hierarchical porous carbon towards a high-performance supercapacitor

Abstract

The massive annual production of polyethylene terephthalate (PET) generates a large amount of waste, thus raising widespread environmental concerns. Converting waste PET into porous carbon materials represents a promising sustainable and green method to reduce its burden on the environment. However, there have been some key challenges with existing carbonization methods, such as a complicated carbonization process and extensive use of corrosive activators. To overcome these challenges, herein, we propose a mild and efficient one-step pyrolysis strategy that can convert waste PET into hierarchical porous carbon (HPC) using K₂CO₃ as an activator/template. The resulting product obtained at a carbonization temperature of 700 °C (HPC-700) showed a unique interconnected hierarchical porous structure and higher oxygen content. The as-prepared HPC-based supercapacitor exhibited an exceptionally high specific capacitance of 332.3 F g⁻¹ at a current density of 0.5 A g⁻¹, which were far higher than those exhibited by previously reported PET-derived carbon counterparts. Furthermore, an excellent rate capability and high cycling stability with 95.98% capacitance retention was achieved after 10 000 cycles. Thus, this work offers a facile and effective approach to converting waste PET into porous carbon materials, showing great potential applications for high-performance capacitors and other energy storage materials. In addition, this study conducted a life cycle assessment (LCA) to understand the ecological impact of the material conversion process.