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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. [ABSTRACT FROM AUTHOR]

Supercapacitors (SCs) based on hierarchical nanoporous framework composite materials and aqueous electrolytes are recent interests for the researchers. The structure of UiO-66 exhibits extraordinary stability and high specific surface area, but the specific capacitance of UiO-66 (139.4 F g–1 at 2 A g–1) is limited due to its moderately conducting nature. Therefore, we report a method to modify UiO-66 with pineapple peel derived activated carbon (PA-AC) to form a facile composite. Owing to the high specific surface area and good conductivity of the UiO-66/PA-AC composite, a high specific capacitance of 295.9 F g–1 at 2 A g–1 has been achieved and is well suited for supercapacitor applications. At the maximum charging voltage range of 0–1.8 V, the UiO-66/PA-AC//UiO-66/PA-AC symmetrical SC delivered a maximum energy density of 29.6 Wh kg–1 at a power density of 170 W kg–1. After 5000 repeated charge–discharge cycles at 30 A g–1, the specific capacitance of the device increased from 100% to 120% of its initial specific capacitance. This study emphasized the potential importance of incorporating MOFs into pores of biowaste derived carbon as a strategy for enhancing the charge storage kinetics of moderately conducting MOFs. [ABSTRACT FROM AUTHOR]

The commercialization of pure carbon-based supercapacitors has faced challenges due to their limited energy density. In order to overcome this challenge, the construction of carbon materials with a hierarchical pore structure has been proposed. Herein, we describe a straightforward template-free method to develop highly nanoporous activated carbon (ACs), via a one-step process where polyaniline (PANI)–polypyrrole (PPy) copolymer is carbonized/activated with KOH in a single step at temperatures ranging from 800 to 1000 °C in N2 environment to get a highly nanoporous ACs. The AC-900 material comprises a network of linked pores and a higher specific surface area of 3899.88 m2/g along with a high electrochemical surface area of 722.05 m2/g, allowing for large amounts of ion storage and quick ion transit. AC-900 has exhibited a very favorable electrochemical performance, in a 1 M H2SO4 electrolyte, a specific capacitance of 1073.9 F/g was achieved when the current density was set to 0.5 A/g. Symmetrical devices were fabricated out of two AC-900 electrodes of equivalent weight, and the results demonstrate that the AC-900//AC-900 device at a power density of approximately 868 W/kg. The device reaches a noteworthy energy density of ∼72 W h/kg, while also demonstrating very high cyclic stability with an efficiency of approximately 100% even after undergoing 6,000 charge–discharge cycles. The impressive electrochemical performance displayed by AC-900 underscores its significant potential as a polymer-derived carbon nanomaterial for electrodes in supercapacitor applications. [ABSTRACT FROM AUTHOR]