Facile synthesis and characterization of MnO2/MWCNT nanocomposites for high-performance asymmetric supercapacitor (original) (raw)
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Controlled synthesis of MnO2/CNT nanocomposites for supercapacitor applications
In this work, manganese oxide (MnO 2)/carbon nanotube (CNT) nanocomposites have been prepared as electrode materials for supercapacitor applications. The materials were synthesised using a traditional and facile chemical deposition method. Effects from CNT amounts, synthesis time, pH value and CNT treatment using nitric acid have been thoroughly investigated. It was found that the sample synthesised for 3 h at pH 5 had achieved the best performance with a specific capacitance of 115 F g 21 at a discharge rate of 0?5 A g 21. A capacitance retention of 95% after 1000 cycles has been observed for the sample synthesised in the neutral environment. We believe that findings from this work will pave a road for nanostructured MnO 2 /CNT composites with better performance in energy storage applications.
International Journal of Electrochemical Science, 2019
Manganese dioxide and multi-walled carbon nanotubes (MWCNT) have received considerable recent interest for their potential application in supercapacitors, MnO2 as a pseudocapacitor material and MWCNT as an electrochemical double layer capacitance (EDLC) material. The combination of MnO2 and MWCNT is expected to make promising supercapacitor electrodes. In this study, MnO2 was mixed with MWCNT during the hydrothermal process. The difficulty in obtaining MnO2/MWCNT composite homogeneity in the hydrothermal process provides a challenge to scaling up production. KMnO4 and MWCNT were mixed with 20 mL distilled water and stirred using a magnetic stirrer for 2 minutes, then placed into an autoclave. Heating of autoclave was carried out at 160°C for 3 hours in an oven and followed by cooling at room temperature naturally. Manganese dioxide/MWCNT composites were made in 1:1 and 3:1 ratios. The diffraction peaks of composites indicated that incorporation of MWCNT into MnO2 has provided a crystalline orientation derived from MnO2 and MWCNT. Scanning electron microscopy and TEM imaging demonstrated that MnO2/MWCNT 3:1 composite attained better homogeneity than MnO2/MWCNT 1:1 as indicated by the attachment of MnO2 to the entire nanotubes surface of MWCNT. Increasing of conductivity values have been supported by MWCNT marked decreasing in the Rct value in electrochemical impedence spectroscopy measurements. Based on cyclic voltammogram measurements, the MnO2/MWCNT electrode 3:1 produced specific capacitation (Cs) of 252 F/g with stability up to 1000 cycles.
2017-MnO2 Nanoflake-Shelled Carbon Nanotube Particles for High-Performance Supercapacitors.pdf
We introduce MnO 2 nanoflake/carbon nanotube (CNT) core−shell particles for high-performance supercapacitors. The CNT particles prepared by drying the CNT-dispersed aerosol produce a tightly intertwined CNT assembly by internal capillary force, and the subsequent growth of MnO 2 on the CNT surface produces a high surface area MnO 2 nanoflake shell. We control the amount of MnO 2 decoration on the CNT particles and obtain a specific capacitance of 370 F/g at current density of 0.5 A/g upon their supercapacitor electrode application. This capacitance is 14 times higher than that of bare CNT particles and 3 times higher than that of bare MnO 2 particles. An asymmetric capacitor based on the MnO 2 / CNT particle is assembled. The capacitor reveals a remarkably high power density of 225 W/kg. This performance is attributed to the contribution of the high pseudocapacitance of a compact MnO 2 nanoflake and the high electrical conductivity of CNT particles with compact packing.
Manganese oxide/MWNTs composite electrodes for supercapacitors
Manganese oxide/multiwalled carbon nanotubes (MWNTs) composite was prepared by mixing manganese oxide and MWNTs through a means of ultrasonic vibration in ethanol solution. A nonaqueous hybrid supercapacitor using manganese oxide/MWNTs (M/M) composite and MWNTs as positive and negative electrodes, respectively, has been designed and investigated by constant current charge/discharge tests. The asymmetric hybrid capacitor has better capacitance and energy characteristics than those of the symmetric ones based on individual M/M composite and MWNTs electrodes. The energy density of the hybrid capacitor can reach 32.91 W h/kg even at a current density of 10 mA/ cm2 in 1.0 M LiClO4 electrolyte, which is comparable to that of a manganese oxide/activated carbon hybrid capacitor.
Synthesis of Carbon-Supported MnO2 Nanocomposites for Supercapacitors Application
Crystals, 2021
In this study, carbon-supported MnO2 nanocomposites have been prepared using the microwave-assisted heating method followed by two different approaches. The MnO2/C nanocomposite, labeled as sample S1, was prepared directly by the microwave-assisted synthesis of mixed KMnO4 and carbon powder components. Meanwhile, the other MnO2/C nanocomposite sample labeled as S2 was prepared indirectly via a two-step procedure that involves the microwave-assisted synthesis of mixed KMnO4 and MnSO4 components to generate MnO2 and subsequent secondary microwave heating of synthesized MnO2 species coupled with graphite powder. Field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma optical emission spectroscopy have been used for characterization of MnO2/C nanocomposites morphology, structure, and composition. The electrochemical performance of nanocomposites has been investigated using cyclic...
Facile synthesis of MnO2-Cu composite electrode for high performance supercapacitor
Journal of Energy Storage, 2021
Here, we report a facile approach for the development of unique nanoporous MnO 2-Cu architecture through a combination of severe surface deformation and dealloying. The severe surface deformation of Cu-Mn alloy prior to selective dealloying resulted in the precipitation of nanoporous MnO 2 in the Cu-rich substrate. The in situ grown nanoporous MnO 2-Cu architecture demonstrated an areal capacitance of 2.8 F/cm 2 at a current density of 5 mA/cm 2 and exhibits an excellent cyclic stability of 95% retention for 4000 cycles at 15 mA/cm 2 current density. The MnO 2-Cu composite structure showed small charge transport resistance of 1.9 Ω as determined using impedance spectroscopy. The asymmetric supercapacitor fabricated using nanoporous MnO 2-Cu as anode and reduced graphene oxide as cathode delivers specific energy of 5.55 Wh kg − 1 at a specific power of 249.75 W kg − 1. The superior performance of nanoporous MnO 2-Cu architecture was attributed to its unique microstructure that ensures high surface area, small internal resistance with rapid charge transport. The current approach can be applied to different material systems and is potentially transformative in the emerging field of advanced supercapacitors.
Nano Tailoring of MnO2 doped Multiwalled carbon nanotubes as electrode materials for supercapacitor
2017
1Research and Development Centre, Bharathiyar University, Coimbatore, Tamil nadu, India 2Department of Physics, Sethu Institute of Technology, Virudunagar, Tamil nadu, India ---------------------------------------------------------------------***--------------------------------------------------------------------Abstract Manganese decorated Multiwalled carbon nanotubes(MCNT) were synthesized through a simple solvo thermal method. The surface morphology and structural analyses of the MnO2 doped MCNT were done using Transmission electron microscope (TEM), Field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) methods. The compositions of the prepared samples were obtained using Energy dispersive spectroscopy (EDS). Morphological studies revealed that a three-dimensional hierarchy architecture built with a highly porous film of interconnected MnO2 found on MCNT surface. The XRD and EDS results revealed that the prepared samples are in pure form without any impu...