Faculty Publications
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Publications by NITK Faculty
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Item Flexible binder free functionalized carbon nanotube electrodes for ultracapacitor(SPIE spie@spie.org, 2014) Badekai Ramachandra, B.R.; Aravinda, L.S.; Bhat, K.U.The Flexible supercapacitor electrode material was prepared by simple spray coating technique. This will provide a greener alternative for the fabrication of binder free composite electrode for supercapacitor applications. A symmetric double layer super capacitor stack was fabricated by using flexible electrodes. The investigation of the capacitance property of the fabricated super capacitor stack was investigated using cyclic voltammetry, chronopotentiometry and electrical impedance spectroscopy studies. The flexible electrode material shows a specific capacitance of 50 Fg-1 with good cyclibility. © 2014 SPIE.Item Magnetron sputtered MoO3/carbon nanotube composite electrodes for electrochemical supercapacitor(Elsevier B.V., 2013) Aravinda, L.S.; Nagaraja, K.K.; Bhat, K.; Badekai Ramachandra, B.Molybdenum oxide (MoO3) has been deposited on multiwalled carbon nanotubes (MWCNTs) using DC reactive magnetron sputtering of molybdenum for supercapacitor applications. The deposits of MoO3 have been developed under different intervals of time. The structure and surface morphology of the deposits have been characterized by means of X-ray diffraction (XRD) analysis and field emission scanning electron microscopy (FESEM). X-ray diffraction peaks of the composite films reveal the formation of crystalline structure of MoO3. The electrochemical performance of the composite films was studied using cyclic voltammetry (CV), galvanostatic charge discharge and electrochemical impedance spectroscopy measurements. The composite film exhibits maximum specific capacitance of 70 F g-1 at a scan rate of 10 mV s-1 in 1 M Na2SO4 electrolyte. The nanocomposite electrode material shows specific capacitance which is almost four fold increase with respect to that of bare MWCNTs. The effect of coating duration on specific capacitance has been studied. The nanocomposite film is found to display good cycleability, even up to 1000 cycles. © 2013 Elsevier Inc. All rights reserved.Item ZnO/carbon nanotube nanocomposite for high energy density supercapacitors(2013) Aravinda, L.S.; Nagaraja, K.K.; Nagaraja, H.S.; Bhat, K.; Badekai Ramachandra, B.A facile, green and highly efficient method for the decoration of carbon nanotubes with ZnO was developed for the fabrication of binder-free composite electrode for supercapacitor applications. The nano composite was prepared by using reactive magnetron sputtering in Ar/O2 environment. This approach leads to more uniform coating with tuneable thickness, which alters the electrochemical performance of the nano composite electrodes. The structure and surface morphology of the composite film have been studied by means of X-ray diffraction (XRD) analysis, scanning electron microscopy and field emission scanning electron microscopy (FESEM). The XRD study reveals the formation of Wurtzite ZnO structure. The electrochemical performance of nano composite electrode was investigated using cyclic voltammetry, chronopotentiometry and electrochemical impedance measurements in non-aqueous electrolyte. The nano composite electrode shows significant increase in the specific capacitance up to 48 F g-1 with an energy density 13.1 Wh kg-1 in the potential range -2 V to 1 V. © 2013 Elsevier Ltd. All rights reserved.Item Nano CeO2/activated carbon based composite electrodes for high performance supercapacitor(2013) Aravinda, L.S.; Bhat, K.; Badekai Ramachandra, B.Cerium oxide (CeO2)/Activated carbon (AC) based composite were prepared by simple mechanical mixing method with high degree of scalability. The samples were characterized using X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM) and Transmission electron microscope (TEM). The composite mixture with 10 wt% (weight %) CeO2 exhibits a specific capacitance of 162 F g-1 in two electrode configuration. The test cell retains 86% specific capacitance even at high current density with excellent cycle stability. The composite electrode exhibits a power density of 3500 W kg-1 at a high current density, suggesting a good electrode material for supercapacitor. © 2013 Elsevier B.V. All rights reserved.Item Binder free MoO3/multiwalled carbon nanotube thin film electrode for high energy density supercapacitors(2013) Aravinda, L.S.; Bhat, K.; Badekai Ramachandra, B.MoO3/multiwalled carbon nanotube (MWCNT) composites were prepared by Magnetron sputtering in Ar/O2 atmosphere. This will provide a greener alternative for the fabrication of binder free composite electrode for supercapacitor applications. MWCNT provides good support for the growth of MoO3 thin films. This integrated composite electrode exhibited specific capacitance of 93 F g-1 and a corresponding energy density of 7.28 Wh kg-1 in non-aqueous electrolyte, which is almost fourfold increase compared to the bare MWCNT. Also the electrode maintains high power density of 4930 W kg-1 at high current rates, suggesting a potential energy storage material for portable and consumer electronics. © 2013 Elsevier Ltd. All rights reserved.Item Porous MnO2 nano whiskers bunch/activated carbon based composite electrodes for high energy density supercapacitor(2013) Aravinda, L.S.; Bhat, K.; Badekai Ramachandra, B.A simple room temperature method was used to synthesize Porous ?-MnO2 nano whiskers bunch. The porous ?-MnO2 /Activated carbon (AC) composites were prepared by very simple mechanical mixing method with varying amount of MnO2. A symmetric supercapacitor stack was fabricated using the prepared composite electrode material. The composite with 30% MnO2 exhibit a maximum specific capacitance of 107 Fg-1 at 1 mAcm-2 in non-aqueous electrolyte. The corresponding energy density was found to be 8.35 Whkg-1. The electrode also exhibits excellent cyclic stability. © 2013 The Electrochemical Society.Item Fabrication and performance evaluation of hybrid supercapacitor electrodes based on carbon nanotubes and sputtered TiO2(Institute of Physics Publishing michael.roberts@iop.org, 2016) Aravinda, L.S.; Nagaraja, K.K.; Nagaraja, H.S.; Bhat, K.U.; Badekai Ramachandra, B.R.We report a simple and eco-friendly method for the fabrication of a titanium dioxide/functionalized multiwalled carbon nanotube (TiO2/FMWCNT) composite electrode for use in supercapacitors. The nanocomposite electrodes were formed by depositing titanium dioxide onto FMWCNTs using reactive magnetron sputtering, thus providing a green roue for the formation of the binder-free composite electrode. It is shown that the electrochemical performance of the fabricated electrodes can be altered by tuning the thickness of the titanium dioxide overlayer. The integrated nanocomposite electrode showed an improved specific capacitance of 90 Fg-1 in two-electrode configuration. © 2016 IOP Publishing Ltd.Item Activated carbon derived from non-metallic printed circuit board waste for supercapacitor application(Elsevier Ltd, 2016) Rajagopal, R.R.; Aravinda, L.S.; Rajarao, R.; Badekai Ramachandra, B.R.; Sahajwalla, V.Activated carbons (ACs) have been synthesized by using waste PCBs via physical activation subsequent to pyrolysis processes. The physical and chemical properties of the produced activated carbons were studied using nitrogen adsorption, FT-IR spectroscopy, RAMAN spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy techniques. Among the synthesized ACs, AC with the highest surface area of 700 m2 g-1 produced at 850 °C for a time interval of 5 h was subjected to electrochemical studies. Capacitance behaviour of the obtained AC sample has been evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge (GC-D) measurements and electrochemical impedance spectroscopy (EIS) technique. Specific capacitance (Cspec) values vary from 220, 185 and 156 F g-1 for corresponding scan rate of 30, 50 and 100 mV s-1 respectively. The well-developed surface area properties and good capacitance values associated with nitrogen functionalities indicates the AC developed is a good and suitable candidate for the supercapacitor fabrication. © 2016 Elsevier Ltd.Item Continuous wave laser probed thermal nonlinearity in TiO2 and TiO2-dye nano colloidal(Elsevier Ltd, 2021) Pramodini, S.; Aravinda, L.S.; Nagaraja, K.K.; Poornesh, P.Herein, we report on the nonlinear optical studies on the nano colloidal solutions of titanium dioxide (TiO2), TiO2-dye and acid blue dye in distilled water under continuous wave laser using the z-scan technique. The phase and structural properties of the sol–gel synthesized TiO2 nanoparticles at different temperatures were analyzed by x-ray powder diffraction (XRD) studies. The transmission electron microscopy (TEM) images confirmed that with an increase in calcination temperature, crystallite size increases. Further, the Fourier transform infrared (FTIR) spectra validate the synthesized TiO2 nano particle's structure. The results from the z-scan reveal self-defocusing and reverse saturable absorption (RSA) behaviors of nano colloidal. The real and imaginary parts of third-order nonlinear optical susceptibility ?(3) were determined and estimated as 10?6 esu. Also, the optical limiting behavior of the samples is studied; a clamping of around ~ 4 mW is observed for the TiO2-dye nano colloidal. © 2021 Elsevier Ltd