Department Of Physics
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Item Mesoporous carbon/titanium dioxide composite as an electrode for symmetric/asymmetric solid?state supercapacitors(Elsevier Ltd, 2022-08-27T00:00:00) Arya, Anil; Iqbal, Muzahir; Tanwar, Shweta; Sharma, Annu; Sharma, A.L.; Kumar, VijayThis paper reports the successful synthesis of mesoporous carbon/titanium dioxide (MC/TiO2) composite electrodes via the hydrothermal method for supercapacitor (SC) applications. The morphology and structural properties of MC/TiO2 composites were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectra (FTIR). The electrochemical properties were recorded by cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD) with an electrolyte (6 M KOH) in symmetric/asymmetric configuration. The specific capacitance (Cs) evaluated by CV is about 280F/g for composite electrode (95 % capacitance retention after 1000 cycles) and pristine has 150F/g @ 10 mV/s. Enhancement in capacitance is owing to faster charge dynamics within electrode material. The fabricated asymmetric device demonstrates high energy density (30.31 Wh/kg), than the symmetric configuration (?27 Wh/kg). Finally, both symmetric/asymmetric supercapacitors have illuminated a red LED, and strengthens the candidature of composite electrode for energy storage technology. � 2022 Elsevier B.V.Item Fabrication of energy storage EDLC device based on self-synthesized TiO2 nanowire dispersed polymer nanocomposite films(Springer Science and Business Media Deutschland GmbH, 2021-05-24T00:00:00) Devi, Chandni; Swaroop, Ram; Arya, Anil; Tanwar, Shweta; Sharma, A.L.; Kumar, SandeepIn this work, a systematic study of titanium oxide (TiO2) nanowires incorporated polymer nanocomposite (PNC) films prepared by a standard solution cast technique is reported. The structural, morphological, dielectric, and electrochemical properties were investigated thoroughly. The polymer nanocomposite films demonstrated improved electrical and electrochemical properties as compared to polymer�salt complex film. The morphological and structural properties have been examined by the field emission scanning electron microscope, Fourier transform infrared spectroscopy, and X-ray diffraction. It is observed that the maximum ionic conductivity is of the order of 10�5 S cm?1 exhibited by 0.5 wt% nanowire added polymer nanocomposite film. The ion transference number was close to unity for optimized film and stability window of about ~ 5�V. The shift of loss tangent peak toward the high-frequency window with nanowire addition indicates a decrease of the relaxation time. The optimized TiO2 nanowire dispersed polymer nanocomposite film has been used to fabricate the electric double-layer capacitor cells. The fabricated cell demonstrates the specific capacitance of about 57.5 F/g (at 10�mV/s). The calculated energy density and power density are 1.38 Wh kg?1 and 0.709�kW�kg?1, respectively. The Coulombic efficiency is 97.7% up to the 500 cycles for the fabricated cell. The prepared polymer nanocomposite has the potential to use it as electrolyte cum separator for solid-state electric double-layer capacitor applications. � 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Item High-performance supercapacitor based on MoS2@TiO2 composite for wide range temperature application(Elsevier Ltd, 2021-06-07T00:00:00) Iqbal, Muzahir; Saykar, Nilesh G.; Arya, Anil; Banerjee, Indrani; Alegaonkar, Prashant S.; Mahapatra, S.K.Transition metal sulphide and their composites gain attention as electrode material in energy storage devices due to their superior properties like excellent conductivity, high surface area, and porosity. We report an evaluation of the electrochemical performance of MoS2@TiO2 binary composite in symmetric supercapacitor assembly at different temperatures. A facile hydrothermal technique is used to prepare MoS2@TiO2 binary composite. Structural and morphological analysis reveals that highly crystalline composite comprising MoS2 assembled in flower-like flake configuration, whereas, TiO2 in nanorods form are prepared. Among all three electrodes, MoS2@15%TiO2 demonstrates maximum specific capacitance 210 F/g at 10 mV/s with excellent cycling stability (98%, 2000 cycles) at ambient temperature. It may be concluded that the mono-phased, mesoporous structure is a key feature behind the improved performance over the other electrodes. Further, improvement in charge-discharge characteristics has been observed by a factor of 200% at 60 �C attributing to low activation energy and faster ion dynamics at elevated temperatures. The impedance spectroscopic analysis reveals a significant reduction in interfacial impedances that leads to a superior capacitance effect compounded with favourable electrolytic charge dynamics. The highest energy density is reported to be 21 Wh/kg with a power density of 1300 W/kg in symmetric configuration. Synergistic effect of the binary system along with unique surface morphology and charge storage followed by intercalation and capacitive mechanism results in enhanced performance of supercapacitor with MoS2@15%TiO2. Thus, binary MoS2@TiO2 composite seems to be an exceptional candidate for the energy storage device operating at a wide temperature range (25�60 �C). � 2021 Elsevier B.V.Item Nanofiller-assisted Na+-conducting polymer nanocomposite for ultracapacitor: structural, dielectric and electrochemical properties(Springer, 2021-01-04T00:00:00) Kamboj, Vashu; Arya, Anil; Tanwar, Shweta; Kumar, Vijay; Sharma, A.L.We report the preparation of ZrO2 nanofiller-incorporated polymer nanocomposite electrolyte based on the PEO-NaPF6 matrix via standard solution cast method. The structure and morphology of polymeric films have been examined with X-ray diffraction and field emission scanning electron microscopy. Different interactions between the polymer, salt and nanofiller have been examined by Fourier transform infrared technique. The temperature-dependent (40�100��C) electrical conductivity has been examined from complex impedance spectroscopy (CIS). The highest ionic conductivity is exhibited by 5�wt% nanofiller-based electrolyte and recorded ~ 2 � 10�4�S�cm?1 at 100��C. The voltage stability window of polymeric film checked from linear sweep voltammetry is about ~ 4�V, and ion transference number close to unity confirms the major contribution from ion conduction. The dielectric properties have been explored in terms of complex permittivity, loss tangent and complex conductivity. The dielectric plots have been further fitted with an associated equation to evaluate principal dielectric parameters. The optimized polymer electrolyte possesses the lowest relaxation time and the highest dielectric constant that suggests the highest ionic conductivity, which is in good correlation with impedance results. The dc conductivity is also highest for the optimum system, and relaxation time decreases with an increase in temperature. The thermal stability of polymer electrolytes is about 200��C, as examined by thermogravimetric analysis (TGA). The ion transport parameters n, ?, D have been evaluated via FTIR, impedance spectroscopy and Bandara and Mellander (B�M) approach. Finally, the optimized polymer nanocomposite film has been used as an electrolyte-cum-separator for the fabrication of a solid-state symmetric supercapacitor. The electrochemical parameters specific capacitance, energy density, power density have been examined from cyclic voltammetry and galvanostatic charge�discharge technique. It may be concluded that nanofiller incorporation is an effective strategy to enhance the properties of electrolyte and has the potential to adopt as an electrolyte-cum-separator for ultracapacitor. � 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.