Department Of Physics
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Item A review on challenges to remedies of MnO2 based transition-metal oxide, hydroxide, and layered double hydroxide composites for supercapacitor applications(Elsevier Ltd, 2022-07-16T00:00:00) Kour, Simran; Tanwar, Shweta; Sharma, A.L.Supercapacitors are emerging energy storage devices admired in the research field due to their tremendous electrochemical properties parameters. Few peculiar properties parameters such as- high capacitance, large specific power/energy, excellent cyclic life, and rapid charging/discharging make them superior to other existing energy storage/conversion systems. Supercapacitors are predicted to be the potential energy resources for vast number of applications ranging from heavy electric vehicles to portable electrical/personal electronic appliances due to their ultra-fast charging behavior. The working efficiency of any supercapacitor is generally reliant on chosen materials acting as an electrode. In electrode materials series, manganese dioxide (MnO2) has been mostly explored and proven to be very effective and promising material as supercapacitor electrode. This is attributable to its superior theoretical capacitance, environmental friendliness, lower price, and vast profusion. But its deprived electrical conductivity and the volume expansion restrict its practical utility as a preferred electrode material. To make full utility of MnO2 materials, its composites with different type of materials have been tried and tested. The most fascinating composite electrode materials with MnO2 are discussed here in detail. The composites discussed in detail are MnO2/Transition metal oxides, MnO2/Transition metal hydroxides, and MnO2/Layered double hydroxides. A complete overview of these composites has been given and finally the recommendation of the best composites has been figured out systematically. The new opportunities for the future towards the advancement of MnO2 based composites are also being highlighted. � 2022 Elsevier LtdItem Study of electrochemical performance of 3-D MnO2 nanoflowers coated with carbon for supercapacitors(Elsevier Ltd, 2022-06-07T00:00:00) Kour, Simran; Tanwar, Shweta; Sharma, A.L.Manganese dioxide has gained wide research attention as a propitious material for supercapacitors attributable to its excellent characteristics like excellent theoretical capacitance, low-price, eco-friendly nature and profound abundance. Here in this paper, we have synthesized MnO2 nanoflowers via a hydrothermal route. The supercapacitive performance of MnO2 was tested. It exhibited a specific capacitance of 73.13 F g?1 at 10 mV s?1. To further boost the electrochemical performance of MnO2 nanoflowers, they have been coated with activated carbon via a very straight-forward sol-gel approach at room temperature. The obtained nano-composite (MnO2/AC) exhibited improved capacitance of 170.68 F g?1 at 10 mV s?1. The composite was able to attain an energy density of 20.89 Wh kg?1 (at 350 W kg?1). Thus, the composite material has broad potential applicability as supercapacitor electrode material. � 2022Item MnO2 nanorod loaded activated carbon for high-performance supercapacitors(Elsevier Ltd, 2022-03-31T00:00:00) Kour, Simran; Tanwar, Shweta; Sharma, A.L.Nowadays, transition metal oxides (TMOs) have gained much attention as potential candidates for supercapacitors owing to their remarkable properties for instance vast abundance, a high value of theoretical capacitance, easy accessibility, and eco-friendly nature. But low electric conductivity of TMOs restrains them from reaching their theoretically predicted value for capacitance. Activated carbon with enormous surface area and excellent conductivity has been chosen to augment the conductivity of TMO-based electrodes. Here in this paper, we have synthesized MnO2 nanorods via a facile hydrothermal process. These nanorods have been loaded onto activated carbon via a straight-forward sol-gel approach at room temperature. The obtained nano-composite exhibited superior capacitance of 398.5 F g?1 at 1 A g?1 than MnO2 (161.8 F g?1). The composite attained excellent energy of 105.2 Wh kg?1 (at 2 kW kg?1). Further, the composite was tested for device application. Three symmetric supercapacitor cells joined in series were proficient to glow a blue LED for about one minute while the red LED was illuminated for about 12 min. This suggested that the composite material has broad potential applicability as supercapacitor electrode material. � 2022 Elsevier B.V.