scholarly journals Synthesis of Carbon-Supported MnO2 Nanocomposites for Supercapacitors Application

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 784
Author(s):  
Jolita Jablonskiene ◽  
Dijana Simkunaite ◽  
Jurate Vaiciuniene ◽  
Giedrius Stalnionis ◽  
Audrius Drabavicius ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cyclic Voltammetry ◽  
Specific Capacitance ◽  
Carbon Powder ◽  
Microwave Assisted Synthesis ◽  
Electrochemical Characteristics ◽  
Galvanostatic Charge ◽  
Microwave Assisted ◽  
Step Procedure ◽  
Charge Discharge

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 voltammetry and galvanostatic charge/discharge measurements in a 1 M Na2SO4 solution. The MnO2/C nanocomposite, prepared indirectly via a two-step procedure, displays substantially enhanced electrochemical characteristics. The high specific capacitance of 980.7 F g−1 has been achieved from cyclic voltammetry measurements, whereas specific capacitance of 949.3 F g−1 at 1 A g−1 has been obtained from galvanostatic charge/discharge test for sample S2. In addition, the specific capacitance retention was 93% after 100 cycles at 20 A g−1, indicating good electrochemical stability.

Microwave-Assisted Synthesis of Graphene Oxide-MnO2 Composites for Supercapacitors

2014 ◽  
Vol 936 ◽  
pp. 607-612
Author(s):  
Ying Wen Duan ◽  
Xun Sun ◽  
Hong Yu Zhao ◽  
Zhi Bo Liu
Keyword(s):  
Cyclic Voltammetry ◽  
Graphene Oxide ◽  
Current Density ◽  
Microwave Assisted Synthesis ◽  
Random Shape ◽  
Galvanostatic Charge ◽  
Microwave Assisted ◽  
Large Numbers ◽  
Microwave Assisted Method ◽  
Charge Discharge

Graphene oxide-MnO2 (GO-MnO2) was successfully synthesized by microwave-assisted method with the substrate of GO covered by MnO2. MnO2 contained disordered pore structure and aggregate of random shape. GO exhibited layer-like shape and had a large numbers of functional groups on its surface. The electrochemical measurements were employed by cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD), the results showed that the GO-MnO2 composite had good capacitive performance, the maximum of specific capacitance was 127 F g-1 at the current density of 100 mA g-1.

Electrodeposition of PANI/MnO2 Composite on SnO2/Ti Substrate for Supercapacitor Electrode

2011 ◽  
Vol 239-242 ◽  
pp. 1372-1375 ◽  
Author(s):  
Ya Kun Zhang ◽  
Jian Ling Li ◽  
Fei Gao ◽  
Xin Dong Wang
Keyword(s):  
Cyclic Voltammetry ◽  
Synergistic Effect ◽  
Specific Capacitance ◽  
Current Density ◽  
Galvanostatic Charge ◽  
Supercapacitor Electrode ◽  
Electrochemical Tests ◽  
A Current ◽  
Charge Discharge

A layer of MnO2 was loaded between the SnO2/Ti substrate and the layer of PANI via a potentiodynamic electrodeposition. Electrochemical tests such as cyclic voltammetry and galvanostatic charge/discharge were applied to investigate the performance of the electrodes. The morphologies of the electrodes were also observed to identify the effect of the MnO2 layer. The specific capacitance of PANI with MnO2 reached to 601.48 F g-1 at a current density of 0.1 mA cm-2, which is 1.69 times as that of PANI electrodes without MnO2 layer. This gratifying result may due to the synergistic effect between MnO2 layer and PANI.

Synthesis of BCN Nanoparticles Sandwiched between Carbon Nanosheets and Performance in Electrochemical Capacitors

2015 ◽  
Vol 719-720 ◽  
pp. 137-140
Author(s):  
Ren Li Yang ◽  
Jun Shuang Zhou ◽  
Li Hou ◽  
Yu Feng Zhao ◽  
Fa Ming Gao
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Properties ◽  
Specific Capacitance ◽  
Current Density ◽  
Nitrogen Atmosphere ◽  
Galvanostatic Charge ◽  
Carbon Nanosheets ◽  
And Performance ◽  
Discharge Measurements ◽  
Charge Discharge

BCN nanoparticles sandwiched between carbon nanosheets were synthesized with the P123 and borate ammonium under nitrogen atmosphere. The samples were characterized by SEM, TEM, and EELS. The SEM and TEM images show BCN nanoparticles are attached on the carbon nanosheets. Cyclic voltammetry (CV) and galvanostatic charge-discharge measurements are used to evaluate electrochemical properties of the composites. The samples show the specific capacitance of 102 F/g at current density of 200mA/g and good durability.

scholarly journals One-Pot Microwave-Assisted Synthesis of Graphene-Supported PtCoM (M = Mn, Ru, Mo) Catalysts for Low-Temperature Fuel Cells

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1431
Author(s):  
Antanas Nacys ◽  
Teofilius Kilmonis ◽  
Virginija Kepenienė ◽  
Aldona Balčiūnaitė ◽  
Raminta Stagniūnaitė ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Microwave Assisted Synthesis ◽  
Electrochemical Characteristics ◽  
One Pot ◽  
Molar Ratios ◽  
Microwave Assisted ◽  
Transmission Electron ◽  
Low Temperature Fuel Cells ◽  
A Current

In this study, one-pot microwave-assisted synthesis was used to fabricate the graphene (GR)-supported PtCoM catalysts where M = Mn, Ru, and Mo. The catalysts with the molar ratios of metals Pt:Co:Mn, Pt:Co:Ru, and Pt:Co:Mo equal to 1:3:1, 1:2:2, and 7:2:1, respectively, were prepared. Catalysts were characterized using Transmission Electron Microscopy (TEM). The electrocatalytic activity of the GR-supported PtCoMn, PtCoRu, and PtCoMo catalysts was evaluated toward methanol oxidation in an alkaline medium employing cyclic voltammetry and chrono-techniques. The most efficient electrochemical characteristics demonstrated the PtCoMn/GR catalyst with a current density value of 144.5 mA cm−2, which was up to 4.8 times higher than that at the PtCoRu(1:2:2)/GR, PtCoMo(7:2:1)/GR, and bare Pt/GR catalysts.

scholarly journals Capacitive behavior of functionalized activated carbon-based all-solid-state supercapacitor

2021 ◽  
Author(s):  
Kyu Seok Lee ◽  
Ye Ji Seo ◽  
Hyeon Taek Jeong
Keyword(s):  
Cyclic Voltammetry ◽  
Activated Carbon ◽  
Solid State ◽  
Specific Capacitance ◽  
Electrochemical Impedance ◽  
Electrochemical Performances ◽  
Galvanostatic Charge ◽  
Capacitive Behavior ◽  
Charge Discharge ◽  
Discharge Curves

AbstractIn this report, we incorporate activated carbon (AC) onto aluminum substrate via doctor blade method to produce an all-solid-state supercapacitor. The electrochemical properties of the all-solid-state supercapacitor were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Galvanostatic charge/discharge tests also were carried out to exhibit stability of the AC-based supercapacitor. The impedance and charge/discharge curves of the all-solid-state supercapacitor showed good capacitive behavior after functionalized AC. The highest specific capacitance obtained for the AC-based supercapacitor was 106 F g−1. About 160% of specific capacitance increased after functionalization of the AC, which indicated that modification of the AC by nitric acid was able to introduce functional groups on the AC and improve its electrochemical performances.

Preparation and Electrochemical Properties of VO2(B) Nano-Belts

2011 ◽  
Vol 694 ◽  
pp. 91-97
Author(s):  
Yu Long Qiao ◽  
Yong Jun Ma ◽  
Qing Ping Luo ◽  
Chong Hua Pei
Keyword(s):  
Cyclic Voltammetry ◽  
Energy Loss ◽  
Electrochemical Properties ◽  
Specific Capacitance ◽  
Hydrothermal Method ◽  
Monoclinic Phase ◽  
Galvanostatic Charge ◽  
Crystal Direction ◽  
Electron Energy Loss ◽  
Charge Discharge

The VO2(B) nanobelts with monoclinic phase were synthesized by a hydrothermal method at 220°C for 48 h in the absence of any surfactants. The electron energy loss spectrum (EELS) demonstrates that vanadium exists only in the 4+ oxidation state. The SEM and TEM images reveal a belt-like structure of the VO2(B) with the length of several micrometers, the width of 140 nm and the thickness of around 20nm and growth along the [110] crystal direction. Cyclic voltammetry (CV) and galvanostatic charge/discharge demonstrate that VO2(B) nano-belts electrode exhibits desirable electrochemical properties and the specific capacitance reaches up to 632.6F•g-1.

scholarly journals Composite C/MnO2 electrodes for electrochemical capacitors based on water electrolyte

2021 ◽  
Vol 21 (3) ◽  
pp. 156-163
Author(s):  
Valentina V. Chernyavina ◽  
◽  
Alexandra G. Berezhnaya ◽  
Igor O. Lepeschkin ◽  
Yaroslava A. Dyshlovaya ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Manganese Oxide ◽  
Isoamyl Alcohol ◽  
Sulfate Solution ◽  
Oxide Nanoparticles ◽  
Electrochemical Characteristics ◽  
Sodium Sulfate Solution ◽  
Galvanostatic Charge ◽  
Manganese Oxide Nanoparticles ◽  
Charge Discharge

The electrochemical properties of C/MnO2 composite materials in 1 M sodium sulfate solution were investigated using the methods of cyclic voltammetry, galvanostatic charge-discharge and impedance spectroscopy. It was shown that the capacitive characteristics of the electrodes depend on the nature and the method of obtaining manganese oxide nanoparticles. It was established that the material containing manganese oxide obtained using isoamyl alcohol as a reducing agent has high electrochemical characteristics.

Li0.95Na0.05Ti2(PO4)3/C with Good Performance as Anode Material for Aqueous Rechargeable Lithium Batteries

2014 ◽  
Vol 989-994 ◽  
pp. 316-319 ◽  
Author(s):  
Jing Zhu ◽  
Yong Guang Liu ◽  
Qing Qing Tian ◽  
Ling Wang ◽  
Ji Lin Cao
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Performance ◽  
Anode Material ◽  
Lithium Batteries ◽  
Sol Gel ◽  
Nasicon Structure ◽  
Galvanostatic Charge ◽  
Rechargeable Lithium Batteries ◽  
Structure And Morphology ◽  
Charge Discharge

Li0.95Na0.05Ti2(PO4)3/C nanocomposite was prepared by sol-gel method.The structure and morphology of the samples were characterized by XRD, SEM which showed the particles had typical NASICON structure and diameter range from 400~500nm. The electrochemical performance were tested by cyclic voltammetry and galvanostatic charge–discharge. Results show Li0.95Na0.05Ti2(PO4)3/C nanocomposite exhibitsmuch better electrochemical performance than bare Li0.95Na0.05Ti2(PO4)3.

Preparation and Electrochemical Properties of LaMnO3 Powder as a Supercapacitor Electrode Material

2017 ◽  
Vol 727 ◽  
pp. 698-704 ◽  
Author(s):  
Xian Wei Wang ◽  
Xiao Er Wang ◽  
Hui Chao Zhang ◽  
Qian Qian Zhu ◽  
Dong Li Zheng ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Properties ◽  
Electrode Material ◽  
Raw Materials ◽  
Sol Gel ◽  
Galvanostatic Charge ◽  
Supercapacitor Electrode ◽  
Lanthanum Manganate ◽  
Pure Phase ◽  
Charge Discharge

The structural and electrochemical properties of lanthanum manganate (LaMnO3) powder prepared by the sol-gel method are researched in this article. The powder calcined at 600 °C showed amorphous, and the powder calcined at 700-800 °C showed the pure phase of the LaMnO3. The grains with the size of about 80-120 nm were agglomerating together. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical properties in alkaline environment. The electrochemical properties calcined at 700 °C showed a specific capacitance of 73 F/g at the current density of 0.5 A/g. The raw materials for preparing the LaMnO3 powder are cheap, and the operation method is simple.

Microwave-Assisted Synthesis of a New Hydantoin Monomer for Antibacterial Polymeric Materials

2009 ◽  
Vol 62 (3) ◽  
pp. 232 ◽  
Author(s):  
Mauro Iannelli ◽  
Fabio Bergamelli ◽  
Giancarlo Galli
Keyword(s):  
Polymeric Materials ◽  
Ethyl Acrylate ◽  
Attenuated Total Reflection ◽  
Polymeric Films ◽  
Microwave Assisted Synthesis ◽  
Chlorination Reaction ◽  
Microwave Assisted ◽  
Low Surface Energy ◽  
Step Procedure ◽  
Biological Tests

11-(4,4-Dimethyl-2,5-dioxoimidazolidin-1-yl)undecyl acrylate was synthesized in a two-step procedure using microwave irradiation. Poly(acrylates) containing fluorinated and hydantoin (5,5-dimethylimidazolidine-2,4-dione) moieties were prepared by free radical polymerization of 2-(perfluorooctyl)ethyl acrylate and the synthesized monomer with the aim of obtaining low surface energy polymeric materials with properties of contact-active biocides. Polymeric films were treated with a bleaching solution in order to convert the hydantoin units to N-halamines, well-known contact-active biocides. The reversibility of the chlorination reaction, necessary to impart a renewable biocide effect, was investigated by Fourier Transform-Attenuated Total Reflection. Preliminary biological tests conducted against Bacillus megaterium demonstrated the effective biocide properties of the prepared materials.

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