Faculty Publications
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Item Organic cation linkers polyoxomolybdate-polypyrrole nanocomposite-based supercapacitors(Springer Science and Business Media Deutschland GmbH, 2021) Muhammed Anees, P.K.; Anandan Vannathan, A.; Kella, T.; Shee, D.; Mal, S.A few new hybrid electrode materials have been synthesized and immobilized for the next-generation energy storage device. The hybrid electrodes PVMo11-TBA, PVMo11-BTA, PVMo11-TBP, PVMo11-TBA-PPy, PVMo11-BTA-PPy, and PVMo11-TBP-PPy were well characterized by NMR, XRD, FTIR, FESEM, BET, and tested for electrochemical performance. Among these hybrid electrode materials, the PVMo11-TBA-PPy electrode shows a high specific capacitance of 144.37 F/g at a 1A/g current density and incredible power and energy density of 1100.16 W/kg and 15.28 Wh/kg, respectively. The high electrode’s capacitance was due to the synergistic effect between the PPy and TBA-PVMo11 and high ionic diffusion compared with other synthesized electrodes. It also exhibited high cycle stability of 72.78% after 4500 cycles at 1 M H2SO4 electrolyte. The EIS offers a lower ESR value of 0.72 ohms for the PVMo11-TBA-PPy than PVMo11-TBA, indicating the rapid charge/discharge rate. On the other hand, the PVMo11-BTA-PPy and PVMo11-TBP-PPy electrodes showed lower capacitance values of 26.98 and 19.53. F/g at 0.4 and 1 A/g current density, respectively. Lowering the capacitance could be the prevention of the interaction of organic cations with the counter polyanion. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Item Electrochemical performance of activated carbon-supported vanadomolybdates electrodes for energy conversion(Elsevier Ltd, 2021) Maity, S.; Anandan Vannathan, A.; Kella, T.; Shee, D.; Das, P.P.; Mal, S.Reinforcing polyoxomolybdates (POMs) into the activated carbon (AC) template engenders a nanohybrid electrode material for high-performance supercapacitor applications. Herein, a first-time novel integration of two polyoxometalates ([PVMo11O40]4-, [PV2Mo10O40]5-) with AC has been demonstrated, and their structural and electrochemical performances were analyzed. AC-VMo11 composite displayed an enhanced capacitance of 450 Fg-1 with an improved energy density of 59.7 Whkg-1. Furthermore, the symmetric supercapacitor cell for AC-VMo11 and AC-V2Mo10 showed high cell capacitances of 38.8 and 20.01 mF, respectively, alongside 99.99% capacitance retention of over 5000 cycles. In addition, the influence of ionic liquid as an electrolyte on AC-V2Mo10 based supercapacitor cell was investigated in tetrabutylammonium bromide (TBAB) electrolyte solution. © 2021 Elsevier Ltd and Techna Group S.r.l.Item Investigations into the supercapacitor activity of bisphosphonate-polyoxovanadate compounds(Academic Press Inc., 2021) Anandan Vannathan, A.; Thakre, D.; Ali, S.R.; De, M.; Banerjee, A.; Mal, S.Electrochemical properties of two different bisphosphonate-polyoxovanadate derivatives have been studied. Both the compounds are oxovanadate polyanion derivatives having formula (NH4)4[H6(VIVO2)(VV2O5)2{O3P–C(O)(CH2-2-C5NH4)-PO3}2]•9H2O (1) and (NH4)4[H6(VIVO2)(VV2O5)2{O3P–C(O)(CH2-3-C5NH4)-PO3}2]•8H2O (2). Compounds 1 and 2 are isostructural mixed-valent polyoxovanadate structures containing 1-hydroxy-2-(2-pyridyl) ethylidene-1,1-bisphosphonate and 1-hydroxy-2-(3-pyridyl) ethylidene-1,1-bisphosphonate, respectively. Composites of these compounds have been prepared with activated carbon (AC), viz. AC-1 and AC-2 for compounds 1 and 2, respectively. In order to investigate the interaction between the parent compounds with activated carbon, the as prepared composites were further characterized using various analytical techniques, such as Infrared spectroscopy, thermal stability analysis, powder X-ray diffraction, FE-SEM, EDX, and surface adsorption studies. Electrodes from these composites have been prepared by deposition upon carbon cloth, and their electrochemical properties, with respect to the supercapacitance behavior, have been extensively studied. The electrochemical performance of both the composite materials have been tested in an aqueous 0.1 ?M ?H2SO4 electrolytic solution. AC-2 displays the highest specific capacitance of 313 ?F ?g?1 at a current density of 1 ?A ?g?1, along with incredible specific energy and power of 43.56 ?Wh kg?1 and 1999.72 ?W kg-1, respectively. Likewise, AC-1 exhibits a specific capacitance of 212 ?F ?g?1 also at the current density of 1 ?A ?g?1 with a specific energy of 29.45 ?Wh kg?1. The AC-2 electrode, therefore, shows more conducting and lower resistivity. As such, composite AC-2 was observed to light up red, green, and blue color LED bulbs for 71, 70, and 15 ?seconds, respectively, with only 42 ?mg of sample coated on carbon cloth, suggesting a remarkable specific power of that material. Comparatively, the composite AC-1 electrode could light up the red LED bulbs for about 190 ?seconds, albeit with 143 ?mg of sample coated on carbon cloth. As such, AC-2 was also observed to retain 98.71% of the electrode stability after 4500 cycles. © 2021 Elsevier Inc.Item Polyoxovanadate-Activated Carbon-Based Hybrid Materials for High-Performance Electrochemical Capacitors(Institute of Physics, 2022) Anandan Vannathan, A.; Chandewar, P.R.; Shee, D.; Mal, S.S.Two different polyoxovanadates derivatives, K5MnIVV11O32.10 H2O (MnV11) and K7MnIVV13O38.18 H2O (MnV13), have been studied to evaluate their electrochemical performance. These polyoxovanadates were deposited on activated carbon (AC) to prepare AC-MnV11 and AC-MnV13 composites. The electrochemical performance of the AC-MnV11 electrode exhibits the remarkable specific capacitance of 479.73 F g-1 at a current density of 0.6 A g-1, along with incredible specific power and energy of 960 W kg-1. Likewise, the AC-MnV13 exhibits a specific capacitance of 357.33 F g-1 at the current density of 0.6 A g-1 with a specific energy of 71.46 Wh kg-1. Interestingly, the AC-MnV11 could light up the red and yellow color LED bulbs for a duration of 80 and 60 s, respectively, indicating a considerable specific power of the material. The AC-MnV13 electrode shows significantly less lighting up during the 65 and 30 s period with red and yellow LED bulbs. © 2022 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.