Upcycling PET waste into CoNi-MOF@MoSe2 hybrid nanostructures for high-performance aqueous supercapacitors.

Abstract

This study presents a novel technique for sustainably upcycling polyethylene terephthalate (PET) plastic waste (PW) into functional metal-organic frameworks (MOFs) for enhanced energy storage applications. To synthesize CoNi-MOF nanocrystals, terephthalic acid (TPA), which is obtained by alkaline hydrolysis of PET, acts as an environmentally benign organic linker. Further integrating the MOFs with ultrathin MoSe2 nanosheets using a simple hydrothermal technique develops a hybrid CoNi-MOF@MoSe2 electrode material. The synthesized nanocomposite demonstrates excellent cycling durability, maintaining 98.46% of its capacitance after 15,000 GCD cycles, along with a high specific capacitance of 3,322 F/g at a low current of 0.5 A/g. Furthermore, an asymmetric supercapacitor (ASC) device was constructed with activated carbon (AC) as the anode and CoNi-MOF@MoSe2 as the cathode in an aqueous KOH electrolyte. This ASC has exceptional electrochemical performance, maintaining 95% of its original capacity after extended cycling and producing a high energy density of 59 Wh kg-1 at a power density of 450 W kg-1. This work highlights the possibility of PW-derived hybrid MOF materials with programmable nanostructures as viable choices for upcoming improved energy storage technologies.