Synthesis and Characterization of Nano-MnO[sub 2] for Electrochemical Supercapacitor Studies

Ragupathy, P.; Vasan, H. N.; Munichandraiah, N.

doi:10.1149/1.2800163

Cited by 227 publications

(156 citation statements)

References 36 publications

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“…It has been shown that the insertion/extraction process happens mostly on well crystallized bulk materials while the adsorption/desorption process occurs on weakly crystallized materials. 48 In light of this report, no redox humps in our CV curves implies that the charge storage process in the present rGO/MnO 2 hybrid electrode system is probably dominated by adsorption/desorption of cations at the MnO 2 surfaces with rich crystalline defects and amorphous interspaces. This is highly agreeable with the structure feature of the MnO 2 nanosheets as observed in the HRTEM image (Fig.…”

supporting

confidence: 52%

In situ anchoring uniform MnO₂ nanosheets on three-dimensional macroporous graphene thin-films for supercapacitor electrodes

Zhao

Meng

et al. 2015

RSC Adv.

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(2015). In situ anchoring uniform MnO2 nanosheets on threedimensional macroporous graphene thin-films for supercapacitor electrodes. RSC Advances: an international journal to further the chemical sciences, 5 (110), 90307-90312. In situ anchoring uniform MnO2 nanosheets on three-dimensional macroporous graphene thin-films for supercapacitor electrodes AbstractWe present a facile and efficient fabrication of 3D macroporous rGO/MnO2 nanosheet thin-films for supercapacitor electrodes. An amorphous-carbon-modified rGO thin-film is firstly prepared through a simple glucose and CaCO3 particle mediated template method. Then ultrathin MnO2 nanosheets are in situ synthesized on the rGO networks by the rapid and scalable redox reaction between KMnO4 and amorphous carbon. The fabricated three-dimensional porous hybrid thin-film shows a high specific capacitance of 245 F g-1 (based on the total mass of the film) at a scan rate of 2 mV s-1, a good rate capability of 143 F g-1 at 300 mV s-1, and an excellent cycling stability, maintaining 81% of the initial capacitance after 2000 cycles at 2 A g-1. The improved performance indicates that the lightweight and low-cost 3D porous rGO/MnO2 nanosheet thin-films have a great potential in the area of portable energy storage devices. , and an excellent cycling stability, maintaining 81% of the initial capacitance after 2000 cycles at 2 A g À1.The improved performance indicates that the lightweight and lowcost 3D porous rGO/MnO 2 nanosheet thin-films have a great potential in the area of portable energy storage devices.

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supporting

confidence: 52%

In situ anchoring uniform MnO₂ nanosheets on three-dimensional macroporous graphene thin-films for supercapacitor electrodes

Zhao

Meng

et al. 2015

RSC Adv.

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“…carbon based supercapacitors). 38 The absence of peaks, corresponding to volumetric intercalation processes (when the redox reaction takes place in a deep portion of the film), is in agreement with a study performed by Ragupathy et al 39 in which the surface redox reactions compensated by cation intercalation process (only in the outer portion of the film corresponding to a few hundred of Angstroms) is predominant in amorphous MnO 2 while the volumetric insertion/extraction process is predominant in crystalline MnO 2 . So that, even that the voltammograms do not show current peaks, it does not mean that the material does not change its oxidation state.…”

Section: Wettability Studiessupporting

confidence: 90%

Macroporous MnO2 electrodes obtained by template assisted electrodeposition for electrochemical capacitors

Benedetti¹,

Petri²,

Torresi³

et al. 2010

J. Braz. Chem. Soc.

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Eletrodos macroporosos de MnO 2 foram preparados por eletrodeposição assistida por molde de partículas esféricas coloidais de poliestireno. A molhabilidade desses filmes foi estudada por medidas de ângulo de contato. Medidas de voltametria cíclica foram realizadas com o objetivo de estudar o seu comportamento como eletrodo para supercapacitores. A capacitância específica obtida foi cerca de 60% maior que a obtida por um eletrodo liso, o que mostra que apesar de a molhabilidade do eletrodo macroporoso ser menor, ocorre alguma penetração do eletrólito pelos poros, aumentando a área eletroativa. Por fim, o eletrodo macroporoso apresentou excelente establidade eletroquímica, não sendo observada queda de capacitância após 1000 ciclos de carga e descarga.Macroporous MnO 2 electrodes prepared by template-assisted electrodeposition using spherical polystyrene colloidal particles are studied. The wettability of such electrodes by a LiClO 4 aqueous electrolyte is measured by the contact angle technique. Cyclic voltammetry experiments are performed in order to evaluate the use of these electrodes for electrochemical capacitor applications. The specific capacity obtained is about 60% higher than that obtained for flat MnO 2 surfaces showing that, in spite of the wettability being lower, some penetration of the electrolyte into the pores must occur, increasing the electroactive area with respect to the flat electrode. Furthermore, the macroporous electrode showed excellent electrochemical stability, with neither a capacitance decrease nor a loss of morphology, after 1000 cycles.Keywords: supercapacitors, manganese oxide, porous electrodes, template assisted electro deposition, wettability IntroductionLi-ion batteries are widely used as energy sources for portable electronic devices, and several studies have been carried out in order to improve their performance.1 As charge/discharge processes are limited by reaction kinetics, 2 the search for devices that can deliver high power is an active field. Electrochemical capacitors or supercapacitors are high power sources that can be fully charged/discharged in seconds because they are based on surface faradaic reactions and/or double-layer capacitance.3,4 These devices can be applied together with a battery in order to allow both high energy and power or to replace conventional capacitors based on electrical charge separation. The preparation of high surface area electrodes can improve device performance because more material is available on the surface for charge compensation as well as for energy storage. 2Concerning redox-active materials for supercapacitors, RuO 2 presents the best capacitance values. However, its high cost does not allow its use in practical applications. 5 An alternative low cost, non toxic and environmentally friend material is MnO 2 .6-9 The electrochemical performance of MnO 2 -based supercapacitors and the mechanism of energy storage depend on several aspects, such as morphology, 10,11 structure 12,13 and post synthesis thermal treatment. 14 The major in...

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“…Recently, a research reports that the insertion/extraction process happens mostly on well crystallized bulk materials while the adsorption/desorption process occurs on weakly crystallized materials. 38 Based on this assumption, there being no obvious redox peaks in CV curves implies that the charge storage process in Mn 3 O 4 @carbon nanorods electrode system may be dominated by adsorption/desorption of cations at the Mn 3 O 4 surface with abundant crystalline defects and amorphous interspaces.…”

Section: Resultsmentioning

confidence: 97%

Manganous-Manganic Oxide@Carbon Core-Shell Nanorods for Supercapacitors with High Cycle Retention

Zhao

Wang

2015

ECS J. Solid State Sci. Technol.

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Very few research has focused on Mn 3 O 4 @carbon nanorod-structured materials for supercapacitor electrode. A facile process has been developed to prepare Mn 3 O 4 @carbon core-shell hybrid nanorods for supercapacitor electrode materials. The core Mn 3 O 4 polycrystals, which are 50 nm in diameter and 500 nm in length, offer faradaic pseudo-capacitance, while at the same time they serve as supporting template for 4.5 nm shell carbon surface, which functions as electrically conductive material and is also beneficial for improving the capacitive performance. It is highly desirable that the hybrid nanorods exhibit an excellent cycle ability with 95% retention after 5000 cycles at 4 A g −1 . The hybrid nanorods present a capacitance of 168 F g −1 and good rate capability (125 F g −1 at 5 A g −1 Sustainable and renewable resources have become more and more important due to climate change and the decreasing availability of fossil fuels. As a result, a continuous and dramatic increase in renewable energy production from wind and sun is observed, as well as the rapid development of vehicles fully powered by electricity with zero carbon dioxide emission. Wind energy and solar power, however, both suffer from instable and inconsistent supply, while a practical car model should be able to run at least a few hours on its own. So largescale, efficient energy storage industry has been flourishing to solve this problem. Batteries and supercapacitors stand at the very front of energy storage industry. 1-3Supercapacitors, also called ultracapacitor, are efficient energy storage units. Those using fast surface redox reaction are called pseudo-capacitors, and those using ion adsorption-desorption are called electrochemical double layer capacitors. They have attracted wide attention around the world over the past decades because of their higher power density, longer cycle life, safer working conditions, higher retention, better environment-friendliness and wider range of working temperatures compared with secondary batteries. And their energy density is much higher than those available in conventional electrical double-layer capacitors. It is undeniable that in order to develop an advanced supercapacitor device, high performance electrode material is indispensable. Active carbon materials, conducting polymers and transition-metal oxides are three fundamental candidates for supercapacitor electrode materials.1,4,5 Unfortunately, none of them are entirely satisfactory. Active carbon materials have long cycle life but low specific capacitance.8 Conducting polymer is well-known for its high flexibility but poor cycle ability.9,10 Transition-metal oxides, such as RuO 2 and MnO x have their unique advantages in their variable oxidation states, good chemical and electrochemical stability, convenience in preparation and high theoretical specific capacitance. However, low porosity, low natural abundance, toxicity and the high cost of RuO 2 have made them unlikely candidates for commercialization of supercapacitors. 11,12 In contrast, manga...

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Synthesis and Characterization of Nano-MnO[sub 2] for Electrochemical Supercapacitor Studies

Cited by 227 publications

References 36 publications

In situ anchoring uniform MnO₂ nanosheets on three-dimensional macroporous graphene thin-films for supercapacitor electrodes

In situ anchoring uniform MnO₂ nanosheets on three-dimensional macroporous graphene thin-films for supercapacitor electrodes

Macroporous MnO2 electrodes obtained by template assisted electrodeposition for electrochemical capacitors

Manganous-Manganic Oxide@Carbon Core-Shell Nanorods for Supercapacitors with High Cycle Retention

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