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Due to demands for sustainability, the interest in energy storage devices constructed from green materials has increased immensely. These devices currently have yet to be satisfactory. Issues include high production costs and toxicity, limited dependability, and subpar electrochemical performance. In this research, low-cost, plant-based electroactive Cu3Mo2O9 materials were synthesized via co-precipitation followed by an annealing method using two different structure-directing agents, i.e., the commonly used surfactant cetyltrimethylammonium bromide (CTAB) and the biomolecule deoxyribonucleic acid (DNA) as a greener alternative, and these materials were studied for the first time. Further, the Cu3Mo2O9 nanoparticles developed using CTAB and DNA were integrated into the lignin matrix and studied as flexible electrodes for supercapacitor application. Here, the morphological advantages of the nanorods and nanosheets formed by varying the synthesis methods and their effects during supercapacitor studies were studied in detail. After 1200 cycles, the Al/lig-Cu3Mo2O9@DNA supercapacitor exhibited higher capacitive performance when compared to the Al/lig-Cu3Mo2O9@CTAB supercapacitor. The Al/Lig-Cu3Mo2O9@DNA supercapacitor had an initial specific capacitance of 404.64 mF g−1 with a ~70% retention, while the Al/Lig-Cu3Mo2O9@CTAB supercapacitor had an initial specific capacitance of 309.59 mF g−1 with a ~50% retention. This study offers a new approach to creating scalable, low-cost, green composite CuMoO4-based electrodes for flexible supercapacitors. [ABSTRACT FROM AUTHOR]

The demand for energy storage devices made from biodegradable materials has increased significantly due to sustainability. Currently, such devices possess vital issues, such as high manufacturing costs and toxicity, low reliability, as well as poor electrochemical performance. In this research, microwave synthesis was conducted to fabricate a low-cost, high-performing, plant-based electroactive material. MnO2 microparticles fabricated via microwave irradiation were deposited on two plant-based materials as substrates made of Al/lignin and Al/AC/lignin. The quasi-solid-state supercapacitors were assembled using a polymeric gel electrolyte of PVA/H3PO4. Scanning electron microscopy was performed to examine the polydispersity, morphology, and porosity of the micro-MnO2 deposited materials. FTIR and UV-vis spectroscopy were performed to study the composition and verify deposition of micro-MnO2 on the lignin-based matrixes. Cyclic voltammetry (CV) was employed to study the polarization resistance of the system. The cyclic charge-discharge (CCD) and electrochemical impedance spectroscopy (EIS) were performed to observe cyclic performance and interfacial resistances. Electrochemical tests showed that after 700 cycles of charge-discharge, both the supercapacitors exhibited high capacitance retention above 90%. Compared to the existing technology, this method enables consistent material structurization with tunable properties due to the controlled heating time and exposure to radiation with minimal waste. This work provides an alternative approach to synthesize low-cost and scalable green composite electrodes for flexible supercapacitors. [ABSTRACT FROM AUTHOR]

In order to meet our increasing energy demand, a flexible, lightweight, and highly organized energy management strategy is needed for flexible supercapacitors. With that perspective, an anode electrode has been designed by depositing NiWO4 nanoparticles on lignin (lig) on an aluminum substrate. A supercapacitor was assembled by using Al/lig–NiWO4 as the anode, Al/AC (activated carbon) as the cathode, and PVA/H3PO4 gel as the electrolyte. Superior electrochemical performance was achieved even after 2000 cycles of charge and discharge study. The maximum specific capacitance at 0.13 A g−1 is 17.01 mF cm−2, which is more than 42 times that reported. The capacitance retention is maintained at about 97% after 1000 cycles, and at 84% after 2000 cycles. The maximum energy and power densities are 2 W h cm−2 and 100 W cm−2, respectively. A series of the composition of lig : NiWO4 : PVDF was tested to optimize the electrochemical performance. It was found that the best performance was achieved for the ratio (10 : 80 : 10) that had predominantly NiWO4 nanoparticles. The remarkable electrochemical performance of this new class of capacitors makes them useful for a wide variety of electronics. [ABSTRACT FROM AUTHOR]