Upcycling Polyethylene Terephthalate-Derived CoNi-Metal-Organic Framework MoSe₂ Hybrids for High-Performance Aqueous...

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 galvanostatic charge-discharge cycles, along with a high specific capacitance of 3322 F g^-1 at a low current of 0.5 A g^-1. Furthermore, an asymmetric supercapacitor (ASC) device is 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.