Sustainable Nanoporous Metal–Organic Framework/Conducting Polymer Composites for Supercapacitor Applications

An economically and environmentally sustainable course of action to address energy crisis concerns is to recycle discarded PET (polyethylene terephthalate) plastics into value-added products for the aforementioned application. Herein, a high surface area Cu-metal organic framework (Cu-MOF) has been synthesized through an economically feasible approach using trash PET plastic. However, electrochemical properties of pristine MOFs are hindered due to their poor stability and low intrinsic conductivity. Hence, high-performance nanocomposites of Cu-MOF with conducting polymers like PANI (polyaniline) and PPy (polypyrrole) have been synthesized via an in situ hydrothermal technique. PANI and PPy not only improve the conductivity of the nanocomposite but also create additional MOF-PANI-MOF transport channels, which ensures effective electrolyte ion transportation and hence enhances the overall electrochemical performance. Cu-MOF/PANI and Cu-MOF/PPy nanocomposites exhibit high specific capacitances of 160.5 and 132.5 F/g, respectively, at a current density of 0.5 A/g, which is more than that of pristine Cu-MOF (104.8 F/g). Furthermore, asymmetric hybrid supercapacitor devices (Cu-MOF//Cu-MOF/PANI and Cu-MOF//Cu-MOF/PPy) have been assembled that have shown immense potential as energy storage devices. The Cu-MOF//Cu-MOF/PANI hybrid device delivered a high energy density of 51.4 Wh/kg at 474 W/kg power density with outstanding cyclic stability, attenuating only 6.6% after 10 000 charge–discharge cycles.