Department Of Physics
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Item Economic and environment friendly carbon decorated electrode for efficient energy storage devices(Elsevier Ltd, 2023-04-26T00:00:00) Singh, Nirbhay; Tanwar, Shweta; Sharma, A.L.; Yadav, B.C.The most dependent storage technologies are secondary batteries and supercapacitors. Supercapacitors are more competent regarding faster energy supply, sustainability, and high-capacity retaining. However, in supercapacitors, most research comprises the least abundant materials that raise the cost and toxicity, which are unfavorable to the environment. Therefore, we have prepared activated carbon-based earth-abundant iron oxyhydroxide material via a low-temperature hydrothermal technique. The key finding of this research is sustainable materials, with co-related studies of TEM and GCD cyclic stability (pre and post-cycling characterizations up to 10k). The X-ray photoelectron spectroscopy analysis reveals the elemental composition of the optimized sample. The electrochemical performance has been tested via galvanostatic charge-discharge analysis, electrochemical impedance spectroscopy, and cyclic voltammetry. The cyclic stability evaluation is done to see the lasting usability of the device for the 10,000th number of charging-discharging cycles, which is supported by electrochemical impedance spectroscopy results in form of a Nyquist plot. The galvanostatic charge-discharge analysis revealed the specific capacitance of 372 F g?1 at 2 mA. The specific energy and power density were obtained as 40 Wh kg?1 and 4200 W kg?1, respectively. The ACF1 shows Coulombic efficiency and capacity retention as 96 % and 80 %, respectively, up to 10k cycles. We have proposed a charge storage mechanism for the fabricated electrode. A supercapacitor has been made-up and tested for the glow of LED, and the device can glow LED for 20 min. The device was repeated after two months and reproduced the LED glow for the same duration. � 2023 Elsevier LtdItem Hierarchical template-free chestnut-like manganese cobaltite for high-performance symmetric and asymmetric supercapacitor(Elsevier B.V., 2022-11-25T00:00:00) Kour, Simran; Tanwar, Shweta; Kour, Pawanpreet; Sharma, A.L.In this work, template-free Chestnut-like MnCo2O4 microspheres are synthesized using a straight-forward hydrothermal process succeeded by calcination. Urea as a reducing/precipitating agent can play an essential role in controlling the morphology of the material without using any additional surfactants or templates. The effect of reducing agent (Urea) on the structural and morphological evolution of MnCo2O4 has been studied. The electrochemical performance of the synthesized materials is investigated in a real device two-electrode cell configuration (symmetric and asymmetric system) rather than a three-electrode configuration. The two-electrode system gives more accurate and practical evaluation of the capacitive behavior of the material. The MnCo2O4 displayed the highest capacitance of 245.34 F g?1 at 5 mV s?1 for 0�1 V in a symmetric cell configuration. It also held an energy density of 22.24 Wh kg?1 at 1500 W kg?1. The optimized sample showed outstanding cyclic performance with only 3% of capacitance loss after 5000 cycles. Based on the structural and electrochemical findings, a charge storage mechanism has been proposed for the symmetric SC. Furthermore, a hybrid asymmetric supercapacitor with MnCo2O4 as a cathode and the previously synthesized MnO2/AC as an anode is also fabricated which exhibited an energy response of 30.12 Wh kg?1 for a power of 7000 W kg?1. For practical applications, different colored LEDs (red, yellow, green, and blue) and a panel with six red LEDs have been illuminated. The panel with six red LEDs is illuminated for 12 mins. for symmetric supercapacitor and 18 mins. for asymmetric supercapacitor. All these remarkable outcomes suggested that the synthesized material has wide potential for supercapacitors. � 2022Item Aging impact of Se powder on the electrochemical properties of Molybdenum selenide: Supercapacitor application(Elsevier Ltd, 2022-02-10T00:00:00) Tanwar, Shweta; Singh, Nirbhay; Sharma, A.L.In the present report, we have studied the impact of aging on selenium (Se) powder in hydrazine hydrate (act as reducing agent) during synthesis of pure molybdenum selenide (MoSe2) material. The MoSe2 as electrode material is prepared via single-step hydrothermal technique with aging Se powder in reducing agent for zero, one, and three days. The structural, microstructural, and chemical nature analysis of the samples was done via XRD, FESEM, and FTIR tools whereas the electrochemical study was performed via CV, GCD, and EIS techniques. The optimized material coded as M 39 (three days aged sample with pH 9) shows a high specific capacitance (Cs) of 368 F g?1 at the current density of value 0.5 A g?1 along with an energy density of 51 Wh kg?1 and power density of 250 W kg?1. Based on the electrode's electrochemical outcomes, it may be indicated that the electrochemical performance of MoSe2 material upsurges as the aging of Se increases from zero to three days. From the obtained results it is could be predicted that the M 39 material may stand appropriate for commercial supercapacitors. � 2022Item High efficient activated carbon-based asymmetric electrode for energy storage devices(Elsevier Ltd, 2022-01-19T00:00:00) Singh, Nirbhay; Tanwar, Shweta; Yadav, B.C.; Sharma, A.L.Electrodes are fabricated using activated carbon@FeOOH and MoSe2. The synthesis of both electrode materials individually is done by a one-step hydrothermal process. The structural, morphological and chemical information's are investigated by XRD, FESEM and FTIR respectively. The electrochemical properties are investigated by EIS, CV and GCD. The Nyquist plot gives the value of Rb and Rct as 1.0 ? and 1.3 ? respectively. The cell shows a maximum specific capacitance of 110 F/g at the scan rate of 40 mV/s and the GCD shows a specific capacitance of 87.5 F/g at a high current density of 10 A/g. The energy density and power density calculated at current density 10 A/g are 31.11 Wh kg?1 and 4479 W kg?1, additionally, the maximum power density is 16000 W/kg, which is obtained at a current density of 40 A/g. The cell shows structural stability up to 5000 cycles with a capacity retention of 79%. The overall electrochemical performance of asymmetric electrodes (activated carbon@FeOOH and MoSe2) indicated its potential application in supercapacitors at commercial scale. � 2022