Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
5 results
Search Results
Item Dual electrochemical application of r-GO wrapped ZnWO4/Sb nanocomposite(Institute of Physics Publishing helen.craven@iop.org, 2019) Brijesh, K.; Bindu, K.; Amudha, A.; Nagaraja, H.S.ZnWO4/Sb nanorods and r-GO-ZnWO4/Sb nanocomposite have been prepared using a single step solvothermal method. The prepared nanocomposites have been characterized using x-ray diffractometer (XRD), Scanning Electron Microscope (SEM), High Resolution Transmission Electron Microscope (HR-TEM), Raman and Brunauer-Emmett-Teller (BET). The x-ray photoelectron spectroscopy (XPS) technique was used to determine the elemental composition of ZWS-5 (5 mg r-GO-ZnWO4/Sb) composite. The XRD reveals the monoclinic wolframite structure of ZnWO4/Sb and r-GO-ZnWO4/Sb. SEM and HRTEM confirms that the ZnWO4/Sb has been decorated on the r-GO sheets. The electrochemical performance of the prepared samples towards the Hydrogen Evolution Reaction (HER) and dopamine sensing has been tested using electrochemical techniques. Onset potential of 265 mV @10 mA cm-2, lower Tafel slope (95 mV dec-1), high electrochemical surface area (1383.216 m2g-1) and high specific site density (18.551 06 × 1021 g-1) of ZWS-5 reveals the high electrocatalytic activity of the composite towards HER. Chronoamperometric dopamine sensing shows that ZWS-5 has the superior sensing performance with highest specific sensitivity (723 ?A ?M-1 ?g-1), lowest limit of detection (0.9624 ?M), along with a good selectivity. Results suggest that the r-GO-ZnWO4/Sb nanocomposite is a good candidate for the HER and electrochemical dopamine sensor. The incorporation of r-GO nanosheets with ZnWO4/Sb (ZWS) nanorods enhances the specific and electrochemical surface area, which accounts for the high electrocatalytic activity of the composite. © 2019 IOP Publishing Ltd.Item Monoclinic Wolframite ZnWO4/SiO2 nanocomposite as an anode material for lithium ion battery(Elsevier B.V., 2020) Brijesh, K.; Dhanush, P.C.; Vinayraj, S.; Nagaraja, H.S.Herein, we report the preparation and characterization of the ZnWO4 and ZnWO4/SiO2 nanocomposite. The ZnWO4/SiO2 nanocomposite exhibits 570 mAh g?1 discharge capacity and 314 mAh g?1 charge capacity at 10 mA g?1 for the primary cycle. The increasing amount of SiO2 in the ZnWO4/SiO2 nanocomposite increases the overall performance of the composite. The synergetic effect between the ZnWO4 and SiO2 enhances the rate capability, specific capacity, cycle stability and coloumbic efficiency of the composite. The good electrochemical performance of ZnWO4/SiO2 nanocomposite makes it a promising anode for Lithium ion battery. © 2020 Elsevier B.V.Item GeO2/ZnWO4@CNT nanocomposite as a novel anode material for lithium-ion battery(Springer, 2020) Brijesh, K.; Nagaraja, H.S.Single-walled carbon nanotube (SWCNT) wrapped GeO2/ZnWO4 nanocomposite was prepared by single-step solvothermal method. In this work, GeO2/ZnWO4 nanocomposites were prepared by varying the molar percentage of GeO2 and by further adding SWCNT for the composite to boost the electrochemical performance. The prepared GeO2/ZnWO4 nanocomposites and GeO2/ZnWO4@CNT nanocomposite are used as anode material for lithium-ion battery (LIB). As expected, GeO2/ZnWO4@CNT nanocomposite exhibits higher capacities and good rate capability than the GeO2/ZnWO4 nanocomposite. The GeO2/ZnWO4@CNT nanocomposite exhibits 930 mAh g?1 discharge capacity and 533 mAh g?1 charge capacity for the initial cycle at 100 mAh g?1 in the voltage range of 0.01–3 V (vs. Li+/Li). Even at high current density of 500 mAh g?1, GeO2/ZnWO4@CNT nanocomposite shows 231 mAh g?1 and 257 mAh g?1 charge/discharge capacity which are higher than that of GeO2/ZnWO4 nanocomposite. The GeO2/ZnWO4@CNT nanocomposite delivers 75.8% capacity retention and 100% coulombic efficiency even after 400 cycles at 300 mAh g?1. These results direct that GeO2/ZnWO4@CNT nanocomposite is a good negative electrode for lithium-ion battery. [Figure not available: see fulltext.]. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.Item Enhanced Electrochemical Performance of Low-Content Graphene Oxide in Porous Co3O4 Microsheets for Dual Applications of Lithium-Ion Battery Anode and Lithium-Ion Capacitor(Springer, 2024) Lakshmi Sagar, G.; Brijesh, K.; Mukesh, P.; Amudha, A.; Bhat, K.S.; Nagaraja, H.S.The enhancement of electrochemical performance in lithium-ion battery (LIB) anode materials through nanostructures is of paramount importance, facilitated by the synergistic integration of these unique architectures with active materials, which increases the availability of active sites and decreases the diffusion path for lithium ions. In this investigation, we successfully synthesized cobalt oxide (Co3O4) microsheets composed of small nanoparticles (measuring 28–33 nm), employing a straightforward hydrothermal process followed by annealing. Furthermore, to enhance the composite’s ability to endure volume changes and increase its electrical conductivity, we created a Co3O4/reduced graphene oxide (rGO) composite embedding a judicious amount of graphene oxide (GO). This engineered composite exhibited remarkable specific discharge capacity of 1081 mAh g−1 at 100 mA g−1, a substantial improvement over the pristine material’s capacity of 718 mAh g−1. The composite demonstrated reduced irreversible capacity loss relative to the pristine counterpart and approached a reversible capacity of nearly 99%. Even after 400 cycles under the demanding conditions of high current density of 500 mA g−1, the composite managed to retain 81% of its initial capacity, underscoring its exceptional cycling stability. Moreover, the application of the Co3O4/rGO//carbon black (CB) assembly in lithium-ion capacitors (LIC) yielded notable energy density of 15.6 Wh kg−1 at elevated power density of 1007 W kg−1. These LIC devices demonstrated robust cyclic stability across extended cycles, sustaining 56% of their initial capacity after 2000 cycles while operating at a current density of 2 A g−1. Graphical Abstract: [Figure not available: see fulltext.]. © 2024, The Minerals, Metals & Materials Society.Item Impact of copper doping on the electrochemical response of MnSe2 as anode for lithium-ion battery(Springer, 2024) Mukesh, P.; Lakshmi Sagar, G.; Brijesh, K.; Kumawat, S.; Hegde, A.; Kumar, A.; Nagaraja, H.S.Transition Metal Chalcogenides (TMC), due to their unique physicochemical properties, are studied in various fields and have potent applications in energy storage applications. This work is based on the synthesis and characterization of copper-doped manganese di-selenide and the effect of its doping on electrochemical performance as anode material for lithium-ion battery applications using the solvothermal method. The characterization techniques used are X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, XPS, UV–visible absorption spectroscopy, and electrochemical analysis. The XRD data confirms the formation of MnSe2 exhibiting Cubic crystal geometry. The FESEM images show the micro-cube-like structure with agglomerated nanocluster nanostructures on the surface with a dimension of 100–200 nm. The doping of the copper has decreased the band gap of the MnSe2, as studied by the UV–visible absorption spectrum. The electrochemical performance is analyzed as anode material for lithium-ion batteries. The charge/discharge measurements show a specific capacity of 706 mAh g−1 as the initial discharge capacity and 336 mAh g−1 as the initial charge capacity at 0.1 A g−1 current density. Meanwhile, 3% Copper-doped MnSe2 showed a better specific capacity of 878 mAh g−1 as the initial discharge capacity and 461 mAh g−1 as the initial charge capacity at 0.1 A g−1 current density. Cyclic stability, rate capability, and electrochemical impedance spectroscopy were performed, and it shows that 3% copper-doped MnSe2 has good stability and better conductivity and charge kinetics, indicating copper doping has enhanced the electrochemical performance of pristine MnSe2. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.