Synthesis of Co2O4 Microspheres by Hydrothermal-Precipitation for Electrochemical Supercapacitors

2009 ◽  
Vol 66 ◽  
pp. 280-283 ◽  
Author(s):  
Zhan Jun Yu ◽  
Ying Dai ◽  
Wen Chen
Keyword(s):  
Specific Capacitance ◽  
High Specific Capacitance ◽  
Precipitation Method ◽  
Potential Candidate ◽  
Cyclic Performance ◽  
X Ray Diffraction ◽  
Prepared Material ◽  
Current Densities ◽  
Hydrothermal Precipitation ◽  
Excellent Stability

Co3O4 microspheres were synthesized by hydrothermal-precipitation method using NH3•H2O, H2O2, n-butanol and polyethylene glycol as precipitator, oxidant, assistant solvent and dispersant respectively. The products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical properties of the Co3O4 electrode were performed by cyclic voltammetry (CV) and galvanostaitc charge/discharge methods. The results exhibited that the Co3O4 single electrode had excellent stability, cyclic performance and high specific capacitance in KOH electrolyte. The specific capacitance as a single electrode was up to 653.74 F/g in the 6mol/L KOH solution with 0-0.4V potential at 2mA/cm2 current density. The effects of electrolyte concentrations and current densities on its capacitive performance were investigated. The Co3O4 prepared material is potential candidate for the preparation of power source devices.

Controlled Synthesis of Different Morphologies of SrWO4 Crystals via a Surfactant-Assisted Hydrothermal Precipitation Method

2013 ◽  
Vol 785-786 ◽  
pp. 449-454
Author(s):  
Yan Zhao ◽  
Chun Yan Wu ◽  
Dan Qin ◽  
Xin Lai ◽  
Si Wu ◽  
...  
Keyword(s):  
Ph Value ◽  
Precipitation Method ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Experimental Parameters ◽  
Infrared Spectrometer ◽  
Luminescent Spectra ◽  
Hydrothermal Precipitation ◽  
Surfactant Assisted

SrWO4 octahedrons, flowers, bundles, ellipsoids and dendrites had been successfully synthesized via surfactant-assisted method. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photo-luminescent spectra techniques (PL) and fourier transrform infrared spectrometer (FTIR). By through various comparison experiments, it can be found that some related experimental parameters including the reagent concentration, [Sr2+]/[WO42-] molar ratio (R), aging temperature and the pH value had great influences on morphology of the products.

A Facile Synthesis of NiFe2O4 with High Specific Capacitance as Supercapacitor Electrode Material

2018 ◽  
Vol 281 ◽  
pp. 854-858
Author(s):  
Xi Cheng Gao ◽  
Jian Qiang Bi ◽  
Wei Li Wang ◽  
Guo Xun Sun ◽  
Xu Xia Hao ◽  
...  
Keyword(s):  
Particle Size ◽  
Specific Capacitance ◽  
Electrochemical Property ◽  
Electrode Materials ◽  
High Specific Capacitance ◽  
Constant Current ◽  
X Ray Diffraction ◽  
Supercapacitor Electrode ◽  
Constant Current Charge ◽  
Supercapacitor Electrode Materials

NiFe2O4 powders were synthesized by a facile hydrothermal method at 180°C followed by a thermal treatment at 300°C. The phase composition and morphology were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results showed that the NiFe2O4 powders were well-crystallized, and they possessed a particle size in the range of 50-100 nm. The electrochemical property was characterized via cyclic voltammetry (CV) and constant current charge-discharge method. Encouragingly, the NiFe2O4 powders had an excellent electrochemical property, whose specific capacitance reached 266.84 F/g at the electric current density of 1 A/g due to the small particle size. Compared with other Fe-based metal compound oxides, NiFe2O4 has a better electrochemical performance, which can be widely used in the supercapacitor electrode materials.

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.

Graphene Oxide/Fe3O4 Composites Prepared via In Situ Precipitation

2014 ◽  
Vol 904 ◽  
pp. 150-154
Author(s):  
Zhe Wei Yang ◽  
Xin Fan ◽  
Li Ang Guo ◽  
Wei Ting Wei
Keyword(s):  
Graphene Oxide ◽  
Specific Capacitance ◽  
Precipitation Method ◽  
Electrochemical Performances ◽  
Composite Electrodes ◽  
X Ray Diffraction ◽  
Bonding Force ◽  
X Ray

The graphene oxide/Fe3O4 composites were prepared by in situ precipitation method in this article. The microstructure and surface morphology of composites were characterized by Fourier transform infrared spectrum, X-ray diffraction and scanning electron microscopy, respectively. Cyclic voltammetry was employed for the determination of specific capacitance and other electrochemical performances. It was shown that there was the chemical bonding force between GO and Fe3O4 particles. And the surfaces of GO were wrapped by the Fe3O4 particles precipitated on the surfaces of GO sheets and no impurities were detected. Furthermore, the specific capacitance of GO/Fe3O4 composite electrodes decreased as Fe3O4 particles reduced and the redox peaks became weaker owing to the addition of nonconductive Fe3O4 particles.

scholarly journals Sol-gel synthesis and electrochemical performance of NiCo2O4 nanoparticles for supercapacitor applications

2019 ◽  
Vol 9 (4) ◽  
pp. 243-253
Author(s):  
Yong Zhang ◽  
Yi Ru ◽  
Hai-Li Gao ◽  
Shi-Wen Wang ◽  
Ji Yan ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Specific Capacitance ◽  
Electrode Materials ◽  
Retention Rate ◽  
Sol Gel ◽  
High Specific Capacitance ◽  
Supercapacitor Electrode ◽  
Electrochemical Tests ◽  
Potential Electrode ◽  
Current Densities

In this work, NiCo2O4 nanoparticles with enhanced supercapacitive performance have been successfully synthesized via a facile sol-gel method and subsequent calcination in air. The morphology and composition of as-prepared samples were characterized using scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray dif­fraction (XRD), and Raman spectroscopy (Raman). The electrochemical per­formances of NiCo2O4 nanoparticles as supercapacitor electrode materials were evalu­ated by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) tests in 3 mol L-1 KOH aqueous solution. The results show that as-prepared NiCo2O4 nanoparticles have diameters of about 20-30 nm with uniform distribution. There are some interspaces between nanoparticles observed, which could increase the effective contact area with the electrolyte and provide fast path for the insertion and extraction of electrolyte ions. The electrochemical tests show that the prepared NiCo2O4 nanoparticles for supercapacitors exhibit excellent electrochemical performance with high specific capacitance and good cycle stability. The specific capacitance of NiCo2O4 electrode has been found as high as 1080, 800, 651, and 574 F g-1 at current densities of 1, 4, 7, and 10 A g-1, respectively. Notably, the capacitance retention rate (compared with 1 A g-1) is up to 74.1 %, 60.3 %, and 53.1 % at current densities of 4, 7, and 10 A g-1, respectively. After 100 cycles, higher capacitance retention rate is also achieved. Therefore, the results indicate that NiCo2O4 material is the potential electrode material for supercapacitors.

scholarly journals Synthesis, structural and optical properties of ZnS nano-particles

2010 ◽  
Vol 7 (1) ◽  
pp. 195-200
Author(s):  
K. K. Dubey ◽  
V. Nayar ◽  
P. S. Choudhary
Keyword(s):  
Band Gap Energy ◽  
Hexagonal Structure ◽  
Nano Particles ◽  
Precipitation Method ◽  
Excitation Wavelength ◽  
X Ray Diffraction ◽  
Prepared Material ◽  
Absorption Experiment ◽  
Zinc Sulfide Nanoparticles ◽  
Co Precipitation

Zinc Sulfide nanoparticles were prepared by chemical rout i.e. co-precipitation method. X-ray diffraction profiles of ZnS have been conformed as single phase with hexagonal structure. And crystalline in nature. The lattice parameters of prepared material is a= 3.8314A0 c=6.2431A0 with space group P63mc. The particle size was determined by scherer formula and found to be 28 nm. The band gap energy of ZnS nanoparticles was determined by optical absorption experiment and found to be 3.68 eV at 300oK. Photoluminescence spectra ware recorded by luminescence spectrophotometer. All the plots contains two peak centered at 315 nm and 425 nm. The excitation wavelength was 250 nm. Appearance of broad peaks centered at 425 nm is attributed to the presence of sulphur vacancies in the lattice.

Thermally reduced graphene oxide/polymelamine formaldehyde nanocomposite as a high specific capacitance electrochemical supercapacitor electrode

2018 ◽  
Vol 6 (14) ◽  
pp. 6045-6053 ◽  
Author(s):  
Ali A. Ensafi ◽  
Hossein A. Alinajafi ◽  
B. Rezaei
Keyword(s):  
Graphene Oxide ◽  
Specific Capacitance ◽  
Reduced Graphene Oxide ◽  
High Specific Capacitance ◽  
Supercapacitor Electrode ◽  
Electrochemical Supercapacitor ◽  
Reduced Graphene ◽  
Excellent Stability

Thermally rGO/polymelamine formaldehyde nanocomposite shows good behavior as supercapacitor electrode with 2271 F g−1 specific capacitance in 10 A g−1 with excellent stability.

scholarly journals Utilization of Lime Mud Waste from Paper Mills for Efficient Phosphorus Removal

2019 ◽  
Vol 11 (6) ◽  
pp. 1524 ◽  
Author(s):  
Hong Vu ◽  
Mohd Khan ◽  
Ramakrishna Chilakala ◽  
Tuan Lai ◽  
Thriveni Thenepalli ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Calcium Hydroxide ◽  
Phosphorus Removal ◽  
Precipitation Method ◽  
Potential Candidate ◽  
X Ray Diffraction ◽  
Paper Mills ◽  
Lime Mud ◽  
Hexagonal Shape

In this study, we utilized lime mud waste from paper mills to synthesize calcium hydroxide (Ca(OH)2) nanoparticles (NPs) and investigate their application for the removal of phosphorus from aqueous solution. The NPs, composed of green portlandite with hexagonal shape, were successfully produced using a precipitation method at moderately high temperature. The crystal structure and characterization of the prepared Ca(OH)2 nanoparticles were analyzed by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The effects of Ca(OH)2 NP dosage and contact time on removal of phosphorus were also investigated. The results show that the green portlandite NPs can effectively remove phosphorus from aqueous solution. The phosphorus removal efficiencies within 10 min are 53%, 72%, 78%, 98%, and 100% with the different mass ratios of Ca(OH)2 NPs/phosphorus (CNPs/P) of 2.2, 3.5, 4.4, 5.3, and 6.2, respectively. Due to the efficient phosphorus removal, the calcium hydroxide nanoparticles (CNPs) could be a potential candidate for this application in domestic or industrial wastewater treatment.

Solvothermal Synthesis of Nanostructured α-Ni(OH)2/ Mesoporous Carbon Composites for Supercapacitors

2011 ◽  
Vol 239-242 ◽  
pp. 1227-1230
Author(s):  
Zhan Jun Yu ◽  
Ying Dai ◽  
Wen Chen
Keyword(s):  
Specific Capacitance ◽  
Mesoporous Carbon ◽  
High Specific Capacitance ◽  
Soft Template ◽  
Carbon Composites ◽  
X Ray Diffraction ◽  
Discharge Current Density ◽  
A Charge ◽  
Discharge Method ◽  
Charge Discharge

Nanostructured α-Ni(OH)2/ mesoporous carbon composites were synthesized by a facile solvothermal method using sodium dodecyle sulfate as a soft template and urea as a hydrolysis-controlling agent. The obtained products were characterized by X-ray diffraction(XRD), and scanning electron microscopy(SEM). Electrochemical properties studies were carried out using cyclic voltammetry(CV) and galvanostaitc charge/discharge method. The results exhibited that the α-Ni(OH)2/ mesoporous carbon composites single electrode had high specific capacitance in KOH electrolyte. The maximum specific capacitance of the α-Ni(OH)2/ mesoporous carbon composites single electrode was up to 2191 F/g in 6 M KOH solution at a charge-discharge current density of 4 mA/cm2, when the mass percent of mesoporous carbon was 5%. It is suggested its potential application in the electrode material for supercapacitors.

Fabrication of Copper Nanowire Coated by Silver Nanocrystal for Protection of Oxidation Transparent Conductive Electrode

2019 ◽  
Vol 948 ◽  
pp. 243-248 ◽  
Author(s):  
Dedi Mardiansyah ◽  
Dyah Uswatun Khasanah ◽  
Kuwat Triyana ◽  
Harsojo
Keyword(s):  
Electron Microscope ◽  
High Performance ◽  
Galvanic Replacement ◽  
Potential Candidate ◽  
X Ray Diffraction ◽  
Transparent Conductive Electrode ◽  
X Ray ◽  
The Stability ◽  
Scanning Electron ◽  
Excellent Stability

Silver is relatively low-abundance in nature and copper have inherent instability to oxidation. The most potential candidate should combine high performance with abundance in nature and excellent stability. In this article, we demonstrated a material with silver nanocrystal coating on to CuNWs by facile galvanic replacement. The analysis of scanning electron microscope, X-ray diffraction, energy dispersive X-ray, and mapping was used for investigating that silver nanocrystal has coated on the CuNWs. This research also studied how the effect of Ag nanocrystal coating to the stability of TCEs CuAgNWs by IV-meter analysis.

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