Department Of Physics
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Item Synergistic improvement in electrochemical performance of Cr-doped MoS2/CuCo2S4 binary composite for hybrid supercapacitors(Elsevier Ltd, 2023-10-31T00:00:00) Kour, Pawanpreet; Kour, Simran; Deeksha; Sharma, A.L.; Yadav, KamleshThe synergistic effect of transition metal doping and composite formation can be imperative to improve the limited conductivity and inferior cyclic stability of MoS2 for supercapacitors. In this work, firstly, the impact of Cr-doping on the electrochemical activity of MoS2 has been discussed. Afterwards, the optimized Cr-doped MoS2 (CrMS-5) sample has been combined with CuCo2S4 (CCS) to further enhance its charge storage ability and cyclic stability. The CrMS-5/CCS composite delivers tremendous electrochemical activity as an electrode with a specific capacity of approximately 1324.08 C g?1 at 4 A g?1. The outstanding performance of the doped binary composite is on account of the synergism between doping and composite formation that results in increased conductivity and numerous redox active sites for charge storage. Furthermore, a symmetric supercapacitor device (SSC) has been fabricated using a CrMS-5/CCS electrode. It attains a high energy density of 46.63 Wh kg?1 corresponding to 1 kW kg?1 of power and exhibits remarkable cyclic stability of 81% for up to 5,000 cycles. The device illuminates a star-shaped LED panel of 12 red LEDs for 30 min. Thus, the above outcomes demonstrate the superiority of the doped MoS2-based composites for high-energy symmetric supercapacitors. � 2023 Elsevier LtdItem MoS2-based core-shell nanostructures: Highly efficient materials for energy storage and conversion applications(Elsevier Ltd, 2023-04-19T00:00:00) Kour, Pawanpreet; Deeksha; Kour, Simran; Sharma, A.L.; Yadav, KamleshMolybdenum disulfide (MoS2) has acquired immense research recognition for various energy applications. The layered structure of MoS2 offers vast surface area and good exposure to active edge sites, thereby, making it a prominent candidate for lithium-ion batteries (LIBs), supercapacitors (SCs), and hydrogen evolution reactions (HERs). However, the limited conductivity, less number of active sites, and structural instability of MoS2 during continuous electrochemical cycling hinder its applications. In this regard, the formation of core-shell structures has been evolving as a prominent approach to uplift the electrochemical/electrocatalytic activity of MoS2 for energy-based applications. The unique core-shell composites of MoS2 with different electro-active materials exhibit superior electrochemical and electrocatalytic properties on account of the synergy of the core and the shell materials. These materials offer huge active area, high conductivity, an easy pathway for charge diffusion, and stable cyclic life leading to their outstanding electrochemical activity. In this review, various core-shell structures of MoS2 with carbon, metal oxides/sulfides, and conducting polymers are discussed for LIBs, SCs, and HERs. The function of core and shell materials in elevating the electrochemical activity of MoS2 based core-shell composites have been explored in detail. The effect of doping of core and shells on the performance of the composite has also been elucidated. The doped MoS2 based core-shell composites manifest tremendous electrochemical performance compared to the un-doped counterpart. Thus, these unique structured core-shell composites are regarded as futuristic candidates for energy storage and conversion systems. � 2023Item Microwave-Induced Rapid Synthesis of MoS2@Cellulose Composites as an Efficient Electrode Material for Quasi-Solid-State Supercapacitor Application(John Wiley and Sons Inc, 2023-03-11T00:00:00) Iqbal, Muzahir; Saykar, Nilesh G.; Mahapatra, Santosh kumarTransition-metal dichalcogenides (TMDs) are highly desired for energy-storage devices due to their intrinsic layered structure, huge surface area, and the large number of active sites. However, the TMDs fail to reach their potential due to restacking of 2D layered structures that remains a major technological hurdle. Herein, MoS2 nanosheets and cellulose fiber binary composite (MoS2@Cellulose) prepared by the microwave-assisted technique are demonstrated as an electrode material for supercapacitor application. The prepared material are tested in symmetric and asymmetric all solid-state device assemblies. It is found that the quasi-solid-state symmetric and quasi-solid-state asymmetric supercapacitors exhibited remarkably higher specific capacitance of ?294 and ?177 F g?1 at a current density of 1 A g?1, respectively, than their counterpart. Furthermore, the symmetric and asymmetric devices deliver excellent energy densities of ?40.84 and ?42.67 Wh kg?1 while maintaining the power density of 400 and 791.81 W kg?1, respectively, and outstanding cyclic stability. The cellulose entanglement causes a reduction in the aggregation and restacking of MoS2, which may improve the electrochemical performance of the supercapacitor. Herein this research, a pathway is provided to create an efficient energy-storage system using 2D materials with sustainable cellulose. � 2023 Wiley-VCH GmbH.Item Mixed-phase MoS2 nanosheets anchored carbon nanofibers for high energy symmetric supercapacitors(Elsevier Ltd, 2023-03-14T00:00:00) Kour, Pawanpreet; Deeksha; Kour, Simran; Sharma, A.L.; Yadav, KamleshMixed-phase MoS2 (MS) nanosheets anchored carbon nanofibers (CNFs) have been synthesized via a hydrothermal route. The concentration of CNFs has been varied in the MS/CNF-x composite (where, x = 1, 1.5, 2, and 3 represents the molar concentration of CNFs) to investigate the impact of CNFs on the electrochemical behavior of the material. The incorporation of CNFs offers a conductive path for the diffusion of ions and provides structural support which limits the restacking of the MoS2 layers during the charging/discharging. The MS/CNF-2 composite delivered superior electrochemical performance compared with the other composites owing to the positive synergy between MoS2 and CNFs. The specific capacitance manifested by MS/CNF-2 (626.08 F g?1 at 1 A g?1) is about four times that of pristine MS (159.35 F g?1). It is also observed that MS/CNF-2 exhibited higher electrochemical stability than pristine MS. Furthermore, the symmetric supercapacitor (SSC) device achieved a tremendous energy density of 42.6 Wh kg?1 at 2.4 kW kg?1. To test its practical applicability, LEDs of different color (red, green, and blue) have been illuminated using a series combination of three symmetric electrode cells. The red, green, and blue LEDs lighted up for 15 mins, 7 mins, and 3 mins. The results demonstrate the superiority of the MS/CNF composite for symmetric supercapacitors. � 2023Item Electrochemical performance of mixed-phase 1T/2H MoS2 synthesized by conventional hydrothermal v/s microwave-assisted hydrothermal method for supercapacitor applications(Elsevier Ltd, 2022-07-05T00:00:00) Kour, Pawanpreet; Deeksha; Yadav, KamleshMixed-phase 1T/2H MoS2 has been receiving immense attention as an electrode material for supercapacitors due to the synergistic effects of both the phases. Herein, we synthesized mixed-phase 1T/2H MoS2 via two different techniques: conventional hydrothermal (HT) and microwave-assisted hydrothermal (MHT) technique. The formation of MoS2 is confirmed through X-ray diffraction pattern, scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman-spectra, and X-ray photoelectron spectra. The electrochemical performance of the two samples is investigated using cyclic voltammetry (CV), Gravimetric charging-discharging (GCD) and electrochemical impedance spectroscopy (EIS). MoS2 synthesized via MHT method (MS-MW) and HT method (MS-HT) deliver capacitances of 421 F g?1 and 742 F g?1 at 5 mV s?1, respectively. The energy density of MS-HT (57 Wh kg?1) is almost double than that of MS-MW (30 Wh kg?1). MS-HT also exhibited remarkable capacitance retention of 91% over 1200 cycles, compared with MS-MW. The results demonstrate that MoS2 synthesized by the hydrothermal method delivers superior electrochemical performance. � 2022 Elsevier B.V.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.