Sustainable Polyethylene Terephthalate Waste-Derived Cu-Based Metal–Organic Framework/Poly(3,4-ethylenedioxythiophene) Hybrids for Redox Symmetrical Supercapacitors

In this study, a highly conductive composite of sustainable waste polyethylene terephthalate (PET) bottle-derived Cu-based metal–organic framework (Cu-MOF)/poly(3,4-ethylenedioxythiophene) (PEDOT) is developed using an in situ hydrothermal technique. The as-obtained Cu-MOF/PEDOT composite is electrochemically evaluated in a 0.2 M K3[Fe (CN)6] + 1 M Na2SO4 redox-additive electrolyte achieving a high specific capacitance of 2013.1 F/g at 3 A/g, and it outperformed the parent material Cu-MOF and also the composite material Cu-MOF/PEDOT in an aqueous electrolyte. This has also been corroborated by surface and diffusion charge characteristics because Cu-MOF/PEDOT in a redox electrolyte shows more diffusion contribution. Moreover, a symmetric device Cu-MOF/PEDOT//Cu-MOF/PEDOT is fabricated, which rendered an extraordinary energy density of ∼69 Wh/kg at an outstanding power density of 749 W/kg and also maintained promising cyclic stability with degradation of only 7.2% of initial capacitance over 10 000 cycles. Hence, this study can be a breakthrough for energy storage applications by making waste-derived sustainable porous MOFs coupled with conducting polymers and a redox-additive electrolyte.