Supercapacitive Properties of Hydrothermally Synthesized γ-MnOOH Nanowires

2013 ◽  
Vol 634-638 ◽  
pp. 2638-2642 ◽  
Author(s):  
Da Zhang Zhu ◽  
Cheng Jiang ◽  
Dong Mei Sun
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
Hydrothermal Process ◽  
High Specific Capacitance ◽  
Electrochemical Analysis ◽  
X Ray Diffraction ◽  
Galvanostatic Charge ◽  
X Ray ◽  
Galvanostatic Discharge ◽  
Discharge Curve

γ-MnOOH nanowires have been synthesized via a simple hydrothermal process without any template at relatively low temperature. The as-obtained sample was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical properties of the γ-MnOOH nanowires were investigated by cyclic voltammetry and galvanostatic charge-discharge methods. And a high specific capacitance calculated from the galvanostatic discharge curve was 191 F•g-1at the current density of 0.1 A•g-1, which remain a good specific capacitance of 143 F•g-1at the current density of 1.0 A•g-1. The electrochemical analysis results demonstrate that γ-MnOOH nanowires should be a good candidate as electrode material for supercapacitor.

Facile hydrothermal synthesis of ternary CeO2–SnO2/rGO nanocomposite for supercapacitor application

2020 ◽  
Vol 13 (02) ◽  
pp. 2051005 ◽  
Author(s):  
Godlaveeti Sreenivasa Kumar ◽  
Somala Adinarayana Reddy ◽  
Hussen Maseed ◽  
Nagireddy Ramamanohar Reddy
Keyword(s):  
Electron Microscope ◽  
Specific Capacitance ◽  
High Performance ◽  
High Specific Capacitance ◽  
Energy Storage And Conversion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Supercapacitor Application ◽  
Transmission Electron ◽  
One Step

In this work, we present the synthesis of a ternary CeO2–SnO2/rGO nanocomposite by using a facile one-step hydrothermal method. The as-synthesized composite was structural, chemical, morphological, elemental information studied by using different characterization techniques X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDAX) and transmission electron microscope (TEM). The CeO2–SnO2/rGO exhibited an excellent specific capacitance of 156[Formula: see text]F[Formula: see text][Formula: see text] at 0.5[Formula: see text]A/g in the presence of 3 M KOH solution. The synergic effect of CeO2, SnO2 and graphene composite coated on Ni foam endowed a high specific capacitance than their individual compounds. This work suggests that the novel ternary composite is a promising candidate for the high performance electrochemical energy storage and conversion systems.

Surface modification and electrochemical properties of activated carbons for supercapacitor electrodes

2015 ◽  
Vol 29 (Supplement 1) ◽  
pp. 1550254 ◽  
Author(s):  
Dan Yang ◽  
Wenmei Qiu ◽  
Jingcai Xu ◽  
Yanbing Han ◽  
Hongxiao Jin ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Specific Capacitance ◽  
Activated Carbons ◽  
Chemical Properties ◽  
Bet Surface Area ◽  
Surface Chemical ◽  
X Ray Diffraction ◽  
Galvanostatic Charge ◽  
X Ray ◽  
Charge Discharge

Modifications with different acids (HNO3, H2SO4, HCl and HF, respectively) were introduced to treat the activated carbons (ACs) surface. The microstructures and surface chemical properties were discussed by X-ray diffraction (XRD), thermogravimetric analysis (TGA), ASAP, Raman spectra and Fourier transform infrared (FTIR) spectra. The ACs electrode-based supercapacitors were assembled with 6 mol ⋅ L[Formula: see text] KOH electrolyte. The electrochemical properties were studied by galvanostatic charge–discharge and cyclic voltammetry. The results indicated that although the BET surface area of modified ACs decreased, the functional groups were introduced and the ash contents were reduced on the surface of ACs, receiving larger specific capacitance to initial AC. The specific capacitance of ACs modified with HCl, H2SO4, HF and HNO3 increased by 31.4%, 23%, 21% and 11.6%, respectively.

MnOx/Ni(OH)2 Nanocomposite Materials for High-Performance Electrochemical Capacitor Application

2012 ◽  
Vol 20 ◽  
pp. 53-60 ◽  
Author(s):  
Zan Wang ◽  
Xin Wang ◽  
Yun Xiao Zhao ◽  
Cui Mei Zhao ◽  
Wei Tao Zheng
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
High Specific Capacitance ◽  
Discharge Process ◽  
Porous Network ◽  
X Ray ◽  
Capacitance Performance ◽  
Charge Discharge

Nanostructured MnOx/Ni (OH)2 composites have been electrodeposited on Ni foam for synthesis of a binder-free electrode for electrochemical capacitors with high specific capacitance and stable electrochemical properties. The microstructure, morphology and chemical composition were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Cyclic voltammetry and galvanostatic charge/discharge measurements were applied to investigate the electrochemical capacitance of the electrode active materials. The results indicated that MnOx acted as a template for growth of Ni (OH)2 with an inter-connected 3D porous network nanostructure. A maximum capacitance value of 2334 F/g at current density of 5 A/g in 1 M KOH electrolyte was achieved, much higher than that of pure Ni (OH)2 and MnOx (992 and 179 F/g, respectively). Moreover, in the charge/discharge process at even larger current density of 20 A/g, the electrode could maintain 82.8 % of the initial specific capacitance after 500 cycles, higher than that of pure Ni (OH)2 (only 46.6% remains). The enhanced capacitance performance was attributed to the synergic effect between the respective single oxides.

Synthesis and Characterization of Nanoflakes β-Ni(OH)2 Microspheres for Supercapacitors

2011 ◽  
Vol 230-232 ◽  
pp. 306-309 ◽  
Author(s):  
Zhan Jun Yu ◽  
Ying Dai ◽  
Wen Chen
Keyword(s):  
Specific Capacitance ◽  
Electrochemical Impedance ◽  
High Specific Capacitance ◽  
X Ray Diffraction ◽  
Discharge Current Density ◽  
X Ray ◽  
A Charge ◽  
Maximum Specific Capacitance ◽  
Charge Discharge

Nanoflakes β-Ni(OH)2microspheres were successfully synthesized by a facile hydrothermal. The microstructures and morphology were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Electrochemical properties studies were carried out using cyclic voltammetry (CV), galvanostaitc charge/discharge and electrochemical impedance spectroscopy methods, respectively. The results exhibited that the β-Ni(OH)2single electrode had high specific capacitance in KOH electrolyte. A maximum specific capacitance of 1929 F/g could be achieved in 6 M aqueous KOH with 0 to 0.4 V potential at a charge-discharge current density of 6 mA/cm2. Therefore, the obtained nanoflakes β-Ni(OH)2microspheres can be a potential application electrode material for supercapacitors.

Electrochemical Performance of Carbon Nanofibers/Cobalt Ferrite (CNF/CoFe2O4) Composites Synthesized by Two Approaches

2021 ◽  
Vol 18 (4) ◽  
Author(s):  
Rounak R. Atram ◽  
Nutan V. Mangate ◽  
Ramdas G. Atram ◽  
Subhash B. Kondawar
Keyword(s):  
Electrochemical Performance ◽  
Specific Capacitance ◽  
Carbon Nanofibers ◽  
Cobalt Ferrite ◽  
Electrochemical Impedance ◽  
X Ray Diffraction ◽  
Galvanostatic Charge ◽  
X Ray ◽  
Excellent Electrochemical Performance ◽  
Hydrothermal Methods

Abstract In this paper, we report the fabrication of activated carbon nanofibers/cobalt ferrite (CNF/CoFe2O4) composites by electrospinning and hydrothermal methods for comparative study of electrochemical properties. The structural, morphological, and compositional analyses of the synthesized composites were examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy. CNF/CoFe2O4 electrodes were investigated for electrochemical behavior using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge–discharge (GCD). The results showed that hydrothermally synthesized CNF/CoFe2O4 composite exhibited the specific capacitance 188.36 F/g, whereas electrospun CNF/CoFe2O4 composite resulted the specific capacitance 106.59 F/g at lowest current density 0.5 A/g. 80% capacitance retention of CNF/CoFe2O4 prepared by hydrothermal as compared with 60% capacitance retention of CNF/CoFe2O4 prepared by electrospinning. These results concluded that CNF/CoFe2O4 electrode obtained by hydrothermal exhibited comparatively excellent electrochemical performance and found its suitability as electrodes for supercapacitors.

Preparation of NiO Nanosheets by Hydrothermal Method and its Electrochemical Capacitive Properties

2016 ◽  
Vol 848 ◽  
pp. 396-400
Author(s):  
Zhong Yang Wang ◽  
Run Hua Fan ◽  
Qian Qian Li ◽  
Lei Qian
Keyword(s):  
Specific Capacitance ◽  
Hydrothermal Method ◽  
Current Density ◽  
Electrochemical Analysis ◽  
Electrical Impedance Spectroscopy ◽  
X Ray Diffraction ◽  
Redox Peak ◽  
Capacitive Properties ◽  
Eis Measurements ◽  
A Current

The precursor Ni (OH)2 was synthesized by a simple hydrothermal method with NiSO4•6H2O and (CH2)6N4 as reactants. Both concentrations of reactants are 0.02 M, 0.04 M, 0.06 M, 0.08 M for experiment contrast, and then NiO was gained after calcination at 400°C. The phase and morphology of the synthesized product were characterized by X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). The electrochemical capacitive characterization was performed using cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrical impedance spectroscopy (EIS) measurements in a 6mol/L KOH aqueous solution electrolyte. The result shows that with the increase of concentrations of reactants, nanosheets stack together and turn into thick slices. CV curves have obvious redox peak, the GCD curves are nonlinear and EIS curves of high frequency area are semicircle. From electrochemical analysis, the capacitance type is pseudocapacitance. And a maximal specific capacitance value when two reactants concentration both are 0.08 M which the specific capacitance decreases from 97 F/g (at a current density of 0.3A/g) to 56 F/g (at a current density of 1 A/g).

Solvothermal Synthesis of Nanostructured Flakes α-Ni(OH)2 Microspheres for Electrochemical Capacitors

2009 ◽  
Vol 79-82 ◽  
pp. 421-424 ◽  
Author(s):  
Zhan Jun Yu ◽  
Ying Dai ◽  
Wen Chen
Keyword(s):  
Specific Capacitance ◽  
Electrolyte Concentration ◽  
Sodium Dodecyl ◽  
High Specific Capacitance ◽  
Soft Template ◽  
X Ray Diffraction ◽  
Electrochemical Capacitance ◽  
X Ray ◽  
Discharge Method ◽  
Facile Solvothermal Method

Nanostructured flakes α-Ni(OH)2 microspheres were successfully synthesized by a facile solvothermal method using sodium dodecyl sulfate as a soft template and urea as a hydrolysis-controlling agent. The obtained products were characterized by Thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Electrochemical properties studies were carried out using cyclic voltammetry, galvanostaitc charge/discharge method, respectively. The results exhibited that the α-Ni(OH)2 single electrode had high specific capacitance in KOH electrolyte. A maximum specific capacitance of the α-Ni(OH)2 single electrode was up to 2398F/g in 6M KOH electrolyte concentration with 0 to 0.4V potential at 4mA/cm2 current density. Furthermore, the effects of the heat treatment temperatures on the electrochemical capacitance of the α-Ni(OH)2 electrodes were investigated.

Selective oxidation of cyclopentene to glutaraldehyde by H2O2 over Nb-SBA-15

2021 ◽  
Author(s):  
yingmeng qi ◽  
Qi Han ◽  
li wu ◽  
Jun Li
Keyword(s):  
Structural Properties ◽  
Selective Oxidation ◽  
Mesoporous Materials ◽  
Hydrothermal Process ◽  
X Ray Diffraction ◽  
X Ray

A series of niobium-containing mesoporous materials Nb-SBA-15 have been prepared by sonication–impregnation and hydrothermal process. The dispersion and structural properties of niobium-containing species were systematically characterized by X-ray diffraction, scanning...

Preparation and Characterization of Pt/Superfine Mesocarbon Microbead Powers Electrocatalysts

2005 ◽  
Vol 3 (3) ◽  
pp. 358-360 ◽  
Author(s):  
Jia Rong-Li ◽  
Wang Cheng-Yang ◽  
Zhu Bin
Keyword(s):  
Reduction Method ◽  
Direct Methanol Fuel Cells ◽  
Electrochemical Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Platinum Particles ◽  
Platinum Electrocatalyst ◽  
Direct Methanol

Superfine mesocarbon microbead powders (SFMCMBs) as the new supports for platinum electrocatalysts were first investigated. The Pt∕SFMCMB electrocatalysts were prepared by an impregnation-reduction method, with hexachloroplatinic acid as the platinum precursor and formaldehyde as the reducing agent. The catalysts were characterized with x-ray diffraction (XRD), field emission gun transmission electron microscope (TEM), and electrochemical analysis. TEM photos showed the platinum particles were dispersed uniformly on the surface of SFMCMBs and there existed a little aggregation of platinum particles in the Pt∕SFMCMB catalysts. The TEM photos showed the existence of the platinum on the supports where the average platinum particle size were 4-6nm. The electrochemical analysis proved that SFMCMBs are excellent candidates to be used as the support of platinum electrocatalyst for methanol electrochemical oxidation as the potential catalyst candidate for direct methanol fuel cells (DMFCs).

Effect of Synthesis Conditions on the Structure and Electrochemical Properties of LiNi1/2Mn1/2O2 by Sol Gel Method

2011 ◽  
Vol 399-401 ◽  
pp. 1447-1450
Author(s):  
Zhi Yong Yu ◽  
Han Xing Liu
Keyword(s):  
Electrochemical Properties ◽  
Sol Gel ◽  
Electrochemical Analysis ◽  
X Ray Diffraction ◽  
Capacity Fading ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Synthesis Conditions ◽  
A Current

The layered LiNi1/2Mn1/2O2 cathode materials were synthesized by a sol gel method. The effects of calcination temperature and time on the structural and electrochemical properties of the LiNi1/2Mn1/2O2 were investigated. The prepared samples were characterized by X-ray diffraction (XRD) and electrochemical analysis. The results revealed that the layered LiNi1/2Mn1/2O2 material could be optimal synthesized at temperature of 900°C for 10h. The sample prepared under the above conditions has the highest initial discharge capacity of 151 mAh/g and showed no dramatic capacity fading during 20 cycles between 2.5-4.5V at a current rate of 20mA/g.

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