Transforming Nonrecyclable Plastic Waste into Cathode Materials for Energy Storage Devices

Abstract

Plastic pollution poses a significant threat to the global health and ecosystem. Repurposing plastic wastes for sustainable energy is a promising approach to mitigate the plastic pollution problem. In this study, plastic waste-derived activated carbon (PWC) is synthesized from nonrecyclable waste and used as a cathode material in lithium–selenium (Li–Se) batteries and zinc-ion hybrid supercapacitors (ZHCs). Increasing the activation temperature (500–800 °C) enhances the specific surface area and pore volume and tailors the porous structure of PWC toward larger pore sizes. PWC activated at lower temperatures with potassium hydroxide (KOH) shows better performance as the Se host in Li–Se batteries due to their microporous structure for effective Se confinement. Se cathode based on PWC activated at 600 °C (PWC600/Se) delivers a reversible discharge capacity of 655.2 mAh g⁻¹ at 0.1 C over 150 cycles. PWC activated at 800 °C (PWC800) possesses the largest surface area of 2328.2 m² g⁻¹ and is thus used to fabricate cathode electrodes for ZHCs. The developed PWC800-ZHC delivers a high energy density of 97 Wh kg⁻¹ at 1600 W kg⁻¹ power density and excellent cycle stability with only 8% capacitance decay after 5000 cycles at 1.0 A g⁻¹.