Faculty Publications
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Item Vanadomanganate as a synergistic component in high-performance symmetric supercapacitor(Elsevier Ltd, 2022) Maity, S.; Anandan Vannathan, A.A.; Chandewar, P.R.; Shee, D.; Das, P.P.; Mal, S.S.Supercapacitor devices fabricated from capacitive and battery-type hybrid electrodes have been projected as a promising energy storage system because of their ability to produce high specific power and energy simultaneously. In this work, we have demonstrated a facile method of impregnation of faradaic type manganese (III) polyoxovanadate, [MnV14O40]−6 on the high surface area substrate of activated carbon (AC) as well as graphene oxide (GO). Materials and electrochemical characterizations data confirm the successful incorporation of capacitive and faradaic type manganese (III) polyoxovanadate into the nanohybrid electrode material. Furthermore, the synergic effect between the carbonaceous nanostructures (AC/GO) and redox-active oxometalate (MnV14) provides a better pathway for ion transport to the interface resulting in enhancement of the conductivity, diffusion ability of the nanohybrid. Moreover, the battery-type MnV14 clusters disperse in the micro/mesopores of AC, whereas the oxygen-containing functional groups in GO act as active sites for anchoring of MnV14 clusters. Thus, the surface modification with MnV14 clusters enhances the specific capacitance of nanohybrid with remarkable electrical and mechanical stability. The AC/MnV14 nanohybrid exhibits an enhanced specific capacitance of 547 F g−1 with specific energy and power of 76 Wh kg−1 and 1600 W kg−1, respectively, at 0.8 A g−1 current density. Additionally, GO/MnV14 shows a specific capacitance of 330 F g−1 with improved specific energy and power of 30 Wh kg−1 and 1276 W kg−1, respectively, at the same current density. Moreover, both the nanohybrids possess excellent cycle stability by retaining 92% (AC/MnV14) and 90.6% (GO/MnV14) of initial capacitance even after 5000 sweeping cycles. © 2021 Elsevier B.V.Item Phosphomolybdic acid embedded into biomass-derived biochar carbon electrode for supercapacitor applications(Elsevier B.V., 2023) J.e, M.; Chandewar, P.R.; Shee, D.; Mal, S.S.In high-performance, clean, safe, and cost-effective ways, supercapacitors are among the most promising ways to store and release nonfossil energy. In recent years, renewable biomass-derived activated carbon has been explored as a potential option for electrode material. It restricts their specific capacitance despite being environment-friendly and possessing intrinsic mechanical strength. In order to overcome this limitation and preserve all other properties, we are infusing polyoxometalate into the activated carbon; this increases specific capacitance with its fast reversible redox behaviour and preserves the carbon's characteristics. Beside suffusing phosphomolybdic acid (PMA) into biomass waste material, such as orange peel-derived activated carbon (OPAC), a new hybrid material (OPAC-PMA) was developed. The nanohybrid design was revealed by structural and morphological research, which showed high interfacial contact, allowing polyanions to redox rapidly. The novel hybrid electrode material (OPAC-PMA) has a capacitance value of 66% higher than the bare OPAC electrode. A further study showed that OPAC-PMA composite showed 88.23% cycle stability in 0.5 M H2SO4 electrolyte at 6 A g−1 for 4000 cycles. © 2023 Elsevier B.V.Item High-performance hybrid supercapacitor-immobilized Wells-Dawson polyoxometalates on activated carbon electrodes(Royal Society of Chemistry, 2023) Madhusree, J.E.; Chandewar, P.R.; Shee, D.; Mal, S.S.The nanofabrication of electroactive hybrid materials for next-generation energy storage devices is becoming increasingly significant as supercapacitor (SC) technology develops rapidly. The present study utilizes activated carbon (AC) templates reinforced with Wells-Dawson polyoxotungstates (POMs) to produce nanohybrid electrodes for high-performance supercapacitors. This study analyzes Wells-Dawson polyoxotungstates (P2W18) for the first time integrated with AC, and its structural and electrochemical performances are discussed. First, the electrochemical performances of symmetric supercapacitors were characterized in an acidic aqueous electrolyte (0.5 M H2SO4). It was observed that a supercapacitor cell containing the 5 wt% AC-P2W18 hybrid symmetric displayed a noteworthy specific capacitance of 289 F g−1 and a remarkable energy density of 40 W h kg−1. Moreover, 5% AC-P2W18 symmetric supercapacitor cells showed 89% cyclic stability over 4000 cycles. Three LED lights were charged onto the electrode. The LEDs continued to illuminate continuously for red until 160 seconds, yellow until 20 seconds, and blue until 10 seconds after removing the electrode from the electrochemical workstation, demonstrating the device's power and energy density. © 2023 The Royal Society of Chemistry.Item High-performance electrochemical supercapacitors based on polyoxometalate integrated into polyaniline and activated carbon nanohybrid(Springer Science and Business Media Deutschland GmbH, 2023) Anandan Vannathan, A.A.; Kella, T.; Shee, D.; Mal, S.S.Polyaniline (PANI) and carbonaceous materials and metallic compounds have played a significant role in energy storage and conversion devices. PANI has demonstrated tremendous potential in the supercapacitor industry due to its high specific capacitance, high flexibility, and economical price. The CPs damage the hierarchical structure during the charging and discharging process and start swelling. Thus, incorporating polyoxometalates (POMs) into the conducting polymer matrix increases the stability of the electrode material. Here, we have demonstrated a comparative study of two newly synthesized composite materials consisting of K5H2[PV4W8O40] ·11H2O, (PV4W8) POM incorporated into two different supports, such as pseudocapacitive polyaniline (PANI) and EDLC activated carbon (AC) matrix. It was observed that the PANI-PV4W8 composite exhibited excellent capacitance nature at 0.5 M H2SO4 electrolyte solution than AC-PV4W8. The PANI-PV4W8 composite demonstrated the specific capacitance of 584 F g−1 at 0.8 A g−1. The composite also exhibited energy and power density of 81Wh kg−1 and 1598 W kg−1, respectively. Besides, the composite shows 93.13% capacity retention after 4500 cycles by cyclic voltammetry measurement at a 500 mV s−1 scan rate. Furthermore, the AC-PV4W8 showed a specific capacitance of 62 F g−1 at the current density of 0.6 A g−1. Interestingly, The PANI-PV4W8 composite could glow up the red and yellow LED bulb for more than a minute, suggesting a promising electrode material for practical supercapacitor purposes. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Item Evaluation of physicochemical properties of citric acid crosslinked starch elastomers reinforced with silicon dioxide(Royal Society of Chemistry, 2024) Pooja, N.; Chakraborty, I.; Mal, S.S.; Bharath Prasad, A.S.; Mahato, K.K.; Mazumder, N.Thermoplastic starch (TPS), derived from renewable resources, offers advantages such as biodegradability and lower production costs compared to petroleum-based plastics. However, its limited mechanical properties pose a challenge for broader applications. This research aims to explore the potential of enhancing the mechanical and barrier properties of TPS films through the incorporation of silicon dioxide as a reinforcement filler and citric acid as a crosslinking agent. By introducing silicon dioxide as a reinforcement filler, the mechanical strength of the TPS films is expected to be improved. Additionally, the incorporation of citric acid as a crosslinking agent is anticipated to enhance the barrier properties of the films. The combination of these additives holds promise for creating TPS films with improved performance, contributing to the development of sustainable and environmentally friendly materials in various industries. The results reveal that SiO2 improves the stiffness of the films at lower concentrations but causes brittleness at higher concentrations. In contrast, citric acid crosslinked films exhibit improved flexibility and density. Scanning electron microscopy demonstrates the morphological changes in the films, with SiO2 affecting surface roughness and aggregate formation. SiO2 reduces film thickness and transparency, while citric acid enhances water resistance and barrier properties. X-ray diffraction analysis shows a reduction in crystallinity due to the plasticization process. Fourier-transform infrared spectroscopy highlights chemical changes and antimicrobial activity is observed with citric acid against specific bacteria. The soil burial test reveals that citric acid crosslinked films exhibit slower degradation due to antimicrobial properties. The combination of SiO2 reinforcement and citric acid crosslinking enhances the overall performance of the films, promising sustainable and environmentally friendly materials for various applications. © 2024 The Royal Society of Chemistry.Item Pseudocapacitive effects of polyoxometalate implanted on graphene oxide matrix with polypyrrole for symmetric Supercapacitor applications(Elsevier B.V., 2024) Biradar, B.R.; Thathron, N.; Das, P.P.; Mal, S.S.Modern technological requirements emphasize designing and manufacturing electrochemical energy storage devices with high energy and power densities and longer cycle life. Supercapacitors with hybrid electrode materials have gained considerable attention as one of these systems due to their potential usage in futuristic applications such as electric vehicles and smart electric grids, among others. In this work, we synthesize potassium 9-tungsto-2-molybdo-1-vanadosilicate K5[α-SiMo2VW9O40]⋅10H2O and graphene oxide (GO) complex treating the latter as the supporting matrix for the former. We prepare the SiMo2VW9-polypyrrole (PPy) complex and then combine that with the GO matrix. The resulting nanohybrids GO-SiMo2VW9 and GO-PPy/SiMo2VW9 are found to have enhanced electrochemical properties when used in symmetric cells. Combining GO and pseudocapacitive materials can augment SC performance owing to their excellent redox properties. GO-SiMo2VW9 and GO-PPy/SiMo2VW9 showed 55.8 % and 85.5 % capacitive behavior at a scan rate of 10 mV/s, suggesting their use as high-performance pseudocapacitive materials as hybrid electrodes. GO-PPy/SiMo2VW9 electrode material shows a specific capacitance of 351.6 F/g with energy and power densities of 48.83 Wh/kg and 999.93 W/kg, respectively, at 0.5 A/g current density. Both the electrode materials yield capacitance retention of 60 % (GO-SiMo2VW9) and 80 % (GO-PPy/SiMo2VW9) after 5000 cycles at an 8A/g current density with almost 100 % coulombic efficiency, implying the stability of the electrode material. © 2024 Elsevier B.V.Item Synergistic Enhancement of Supercapacitor Performance: Vanadium-Substituted Phosphotungstic and Molybdic Acid Combined with Polypyrrole Using Pyridinium and Ammonium Ionic Containing Organic Cation Linkers with Improved Conductivity(John Wiley and Sons Inc, 2024) Puniyanikkottil, M.A.; Chandewar, P.R.; Shee, D.; Mal, S.S.High-performance energy-storage devices have emerged as a favored choice owing to their remarkable efficiency, sustainability, and environmental friendliness. Nowadays, polyoxometalate (POM)-based supercapacitor (SC) electrode materials have gained much attention. Herein, a few new POMs and ionic liquid (IL) composites incorporated into conducting polymer as electrode materials for SC applications are reported. The H6[PV3Mo9O40]⋅34H2O (PV3Mo9) and H6[PV3W9O40].34H2O (PV3W9) POMs are treated with tetrabutylammonium chloride and 1-butyl-4-methyl pyridinium chloride (BMP) and finally combined with polypyrrole (PPy) for the SC studies. An extensive array of analytical techniques is employed to delve into the interplay between the constituents within the composite materials, such as Fourier transform infrared spectroscopy, powder X-ray diffraction, thermogravimetric analysis, nuclear magnetic resonance (1H and 13C), Field-emission scanning electron microscopy, energy-dispersive X-ray stpectroscopy, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller surface area. The combined application of these techniques enables us to understand the interaction dynamics within composite materials comprehensively. POM–ILs combination improves the solubility issues of POMs, and doping of PPy enhances the electrochemical performances of the materials. The PV3W9–BMP–PPy symmetric SC cell shows a specific capacitance of 294.79 F g−1 and an energy density of 28.89 Wh kg−1 at 1 A g−1 current density in 0.25 M H2SO4 medium followed by an excellent cycle life of 78.6% after 10,000 galvanostatic charge–discharge cycles. The fabricated SC device is performed to light up the bulbs of red, yellow, and green light emitting diodes for 50, 30, and 28 s, respectively. © 2024 Wiley-VCH GmbH.Item Dual-functional phosphomolybdic acid–polypyrrole–ionic liquid nanocomposites for energy storage and hydrogen evolution: experimental and theoretical studies(Royal Society of Chemistry, 2025) Anees, M.P.K.; Iniyan, S.; Pratap Singh, C.; Murugavel, M.; Krishnamurty, S.; Mal, S.S.Recent advancements in pseudocapacitive materials for energy storage and catalytic activities highlight the benefits of incorporating nanostructured active materials. This study investigates the modification of polypyrrole (PPy) surfaces using polyoxometalate H4[PVMo11O40].xH2O (PVMo11) combined with ionic liquids hexadecyltrimethylammonium chloride (CTAC) and 1-benzyl-3-methylimidazolium chloride (BMI). Among various synthesized nanocomposites, PVMo11-BMI-PPy demonstrated superior electrochemical properties in a 0.25 M H2SO4 aqueous electrolyte, achieving a remarkable specific capacitance of 400 F g?1, an energy density of 49.5 W h kg?1 and a power density of 906 W kg?1 at a current density of 1 A g?1. It achieves a capacitive contribution of 94.5% at 10 mV s?1 with an impressive cyclic retention rate of 91.1% and a coulombic efficiency of 98.9% after 10?000 GCD cycles. Additionally, PVMo11-BMI-PPy exhibited outstanding electrocatalytic activity for hydrogen evolution reaction (HER), achieving the highest catalytic activity of 19 mV at a current density of 10 mA cm?2, outperforming the benchmark Pt catalyst. Its superior performance is underscored by a high TOF of 6.91 × 10?7 s?1 and excellent long-term stability in 0.5 M H2SO4 over 24 hours. It is a promising candidate for bifunctional activities such as energy storage and catalytic applications. Additionally, density functional theory (DFT) studies were conducted to gain insights into the enhanced performance of PVMo11-BMI-PPy. The thermodynamic and electronic characteristics indicate that the V site of PVMo11-BMI-PPy offers the most efficient and balanced catalytic environment for hydrogen evolution reaction (HER) compared with all other sites examined. These theoretical findings align well with experimental observations, demonstrating superior HER activity of the PVMo11-BMI-PPy catalyst, thereby confirming the computational predictions. This journal is © The Royal Society of Chemistry, 2026