The Capacitive Behavior of Ni0.76Co0.24Ox Xerogels in KOH Solution

2012 ◽  
Vol 608-609 ◽  
pp. 1092-1096
Author(s):  
Jie Cheng ◽  
Xin Jin Tian ◽  
Yue Hua Wen ◽  
Yan Xu ◽  
Han Min Liu ◽  
...  
Keyword(s):  
High Performance ◽  
Electrode Materials ◽  
Sol Gel ◽  
Constant Current ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Capacitive Behavior ◽  
Heat Treated ◽  
A Current

Ni0.76Co0.24Ox xerogels were formed by the sol-gel method followed by heat-treatment in air. The structure and properties of these materials were characterized by using X-ray diffraction, TEM and N2 (77K) adsorption. Electrodes with the xerogels were activated by cyclic voltammetry (CV) and their capacitive performance was evaluated by galvanostatic technique in 7 mol/L KOH solutions. A maximum specific capacitance of 904 F/g was obtained by constant current discharge with a current density of 2.0 mA/cm2 for the Ni0.76Co0.24Ox xerogels heat-treated at 250°C. High performance obtained indicates that these materials are promising electrode materials for supercapacitors.

Capacitive Study of Ni(OH)2 Xerogels in KOH Solution

2012 ◽  
Vol 608-609 ◽  
pp. 1106-1110
Author(s):  
Xin Jin Tian ◽  
Jie Cheng ◽  
Yue Hua Wen ◽  
Gao Ping Cao ◽  
Han Min Liu
Keyword(s):  
Cyclic Voltammetry ◽  
High Performance ◽  
Electrode Materials ◽  
Ambient Pressure ◽  
Sol Gel ◽  
Constant Current ◽  
Electrochemical Activation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Average Size

Ni(OH)2 xerogels were formed by sol-gel method at 80 °C followed drying at 110 °C and ambient pressure. The structure of Ni(OH)2 xerogels was characterized using X-ray diffraction, transmission electron microscope (TEM) and N2 (77K) adsorption. X-Ray Diffraction (XRD) results showed that the material obtained has a crystalline -Ni(OH)2. TEM images showed that average size of the crystalline phase is about 10 nm. Results of N2 (77K) adsorption isotherm showed that the (BET) specific surface area is 232 m2/g and the Pore size distribution is in the regime 1-4 nm (Barrett–Joyner–Halenda, BJH). The Ni(OH)2 xerogels electrodes were activated using cyclic voltammetry, and their capacitive performance was evaluated using cyclic voltammetry (CV) and constant current discharge. The Ni(OH)2 xerogels electrodes exhibited excellent capacitive behavior with a specific capacitance of 635 F/g (calculated by CV). High performance obtained indicates that the Ni(OH)2 xerogels are promising electrode materials for supercapacitors, and the electrochemical activation of these electrodes is doable.

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.

scholarly journals Nitrogen, Phosphorus and Sulfur Co-Doped Pyrolyzed Bacterial Cellulose Nanofibers for Supercapacitors

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1912
Author(s):  
Zheng Li ◽  
Yaogang Wang ◽  
Wen Xia ◽  
Jixian Gong ◽  
Shiru Jia ◽  
...  
Keyword(s):  
Bacterial Cellulose ◽  
High Performance ◽  
Electrode Materials ◽  
Cellulose Nanofibers ◽  
Electrochemical Performances ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Nitrogen Phosphorus ◽  
Co Doped

Heteroatom doping is an effective way to raise the electrochemical properties of carbon materials. In this paper, a novel electrode material including nitrogen, phosphorus, and sulfur co-doped pyrolyzed bacterial cellulose (N/P/S-PBC) nanofibers was produced. The morphologies, structure characteristics and electrochemical performances of the materials were investigated by Scanning electron microscopy, Fourier transform infrared spectra, X-ray diffraction patterns, X-ray photoelectronic spectroscopy, N2 sorption analysis and electrochemical measurements. When 3.9 atom% of nitrogen, 1.22 atom% of phosphorus and 0.6 atom% of sulfur co-doped into PBC, the specific capacitance of N/P/S-PBC at 1.0 A/g was 255 F/g and the N/P/S-PBC supercapacitors’ energy density at 1 A/g was 8.48 Wh/kg with a power density of 489.45 W/kg, which were better than those of the N/P-PBC and N/S-PBC supercapacitors. This material may be a very good candidate as the promising electrode materials for high-performance supercapacitors.

Electrochemical Performance of La0.7Sr0.3Cu1-xFexO3-δ as Cathode Material in IT-SOFCs

2010 ◽  
Vol 160-162 ◽  
pp. 666-670
Author(s):  
Min Zhang Zheng ◽  
Xiao Mei Liu
Keyword(s):  
Electrical Conductivity ◽  
High Temperature ◽  
Cathode Material ◽  
Single Phase ◽  
Cathodic Polarization ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cathodic Overpotential ◽  
A Current

To obtain more detail information about the cathode of La0.7Sr0.3Cu1-xFexO3-δ（x= 0.1,0.3,0.5,0.7,0.9）in IT-SOFCs, the cathode material La0.7Sr0.3Cu1-xFexO3-δ（x=0.1, 0.3, 0.5, 0.7, 0.9）was synthesized by a sol-gel method. X-ray diffraction revealed it to be form a single phase of perovskite. The high temperature electrical conductivity was measured by using the four-point dc technique, and cathodic overpotential with SDC（Sm0.15Ce0.85O1.925） electrolyte support was measured by using a current-interruption technique. The investigation of electrocheimical properties suggested that La0.7Sr0.3Cu0.7Fe0.3O3-δ has the highest electrical conductivity and the lowest cathodic polarization. Using La0.7Sr0.3Cu0.7Fe0.3O3-δ as cathode and 65%NiO/SDC as anode based on SDC electrolyte one can obtain higher current density and power density at intermediate temperatures, La0.7Sr0.3Cu0.7Fe0.3O3-δ is considered to be a possible cathode adapted to IT-SOFCs.

Microwave Processing of Sol-Gel Derived Potassium Niobate

1990 ◽  
Vol 180 ◽  
Author(s):  
Z. Fathi ◽  
I. Ahmad ◽  
D.E. Clark
Keyword(s):  
Sol Gel ◽  
Microwave Energy ◽  
Phase Changes ◽  
Conventional Heating ◽  
Potassium Niobate ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Novel Processing ◽  
The Relationship

ABSTRACTMicrowave energy has been used in a novel processing method. The relationship between processing, structure and properties of sol-gel-derived potassium niobate sol as well as thin films has been investigated. A comparison has been established between microwave and conventional heating for drying, calcining and crystallizing sol-gel-derived samples. Structural and phase changes were monitored by thermogravimetric analysis (TGA), differential thermal analysis (DTA) and x-ray diffraction (XRD).

Properties of SiO2CuOx Films for Nitrogen Dioxide Detection

2013 ◽  
Vol 834-836 ◽  
pp. 112-116 ◽  
Author(s):  
Tatiana Myasoedova ◽  
G.E. Yalovega ◽  
V.V. Petrov ◽  
O.V. Zabluda ◽  
V.A. Shmatko ◽  
...  
Keyword(s):  
Thin Films ◽  
Nitrogen Dioxide ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gel Technique ◽  
Operating Temperatures

SiOxCuOythin films were prepared by the deposition on to the Si/SiO2substrates from the alcoholic solutions employing the sol-gel technique. The various analytic techniques were applied to characterize structure and properties of the films under study . The both X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) studies showed the presence CuO as well as CuO2phases and formation of a dual-oxide CuSiO3with the average crystallites sizes of 35-50 nm. The conductance of the films was rather sensitive to the presence of 1-20 ppm NO2concentration at the operating temperatures in the range of 20–200◦C.

scholarly journals Titania-Coated Alumina Foam Photocatalyst for Memantine Degradation Derived by Replica Method and Sol-Gel Reaction

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 227 ◽  
Author(s):  
Zrinka Švagelj ◽  
Vilko Mandić ◽  
Lidija Ćurković ◽  
Martina Biošić ◽  
Irena Žmak ◽  
...  
Keyword(s):  
Tio2 Nanoparticles ◽  
Tio2 Film ◽  
High Performance ◽  
Light Emitting Diode ◽  
Sol Gel ◽  
Dip Coating ◽  
Replica Method ◽  
X Ray Diffraction ◽  
Characterization Methods ◽  
X Ray

In the present work, alumina (Al2O3) foam was prepared by the replica method where a polyurethane (PU) foam (30 pores per inch (ppi)) template was impregnated with a 60 wt.% Al2O3 suspension. Sintered Al2O3 foam was used as substrate for the deposition of sol-gel derived titania (TiO2) film using dip coating. For the preparation of TiO2 sol, titanium(IV) isopropoxide (Ti-iPrOH) was used as the precursor. The common problem of qualification and quantification of a crystalline coating on a highly porous 3D substrate with an uneven surface was addressed using a combination of different structural characterization methods. Using Powder X-ray Diffraction (PXRD) and synchrotron Grazing Incidence X-ray Diffraction (GIXRD) on bulk and powdered Al2O3 foam and TiO2-coated Al2O3 foam samples, it was determined Al2O3 foam crystallizes to corundum and coating to anatase, which was also confirmed by Fourier Transformed Infrared Spectroscopy (FTIR). Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM/EDS) revealed the structural and microstructural properties of the substrate and coating. Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA) were used to clarify the evolution of the porous microstructure. The Al2O3-TiO2 composite was evaluated as a photocatalyst candidate for the degradation of the micropollutant medication memantine. The degradation rate was monitored using a light-emitting diode (LED) lamp operating at electromagnetic (EM) wavelength of 365 nm. The photocatalytic activity of sol-gel-derived TiO2 film immobilized on the Al2O3 foam was compared with commercially available TiO2 nanoparticles, P25-Degussa, in the form of a suspension. The levels of memantine were monitored by High-Performance Liquid Chromatography–Tandem Mass Spectrometry (HPLC–MS/MS). The efficiency and rate of the memantine photodegradation by suspended TiO2 nanoparticles is higher than the TiO2-coated Al2O3 foam. But, from the practical point of view, TiO2-coated Al2O3 foam is more appropriate as a valuable photocatalytic composite material.

Study of Dose—Envelope Reactions in Metal Halide Discharge Lamps Using Raman Microscopy

2002 ◽  
Vol 56 (8) ◽  
pp. 1013-1020
Author(s):  
Robert J. Forrest ◽  
Robin Devonshire ◽  
Chakrapani V. Varanasi ◽  
Timothy R. Brumleve
Keyword(s):  
Raman Spectra ◽  
Electrode Materials ◽  
Raman Microscopy ◽  
Metal Halide ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Raman ◽  
Heat Treated

Raman microscopy has been used to investigate the reactions between the chemical dosants in scandium metal halide discharge lamps and their silica lamp envelopes; such lamps are typically dosed with Hg, NaI, ScI3, and sometimes, additionally, excess Sc metal. Raman measurements were made both on operated lamps and dosed silica ampoules that had been furnace heat-treated. The ampoules mimic closely the dose–envelope interactions of lamps in a convenient manner while avoiding the obscuring and complicating effects in whole-lamp studies resulting from the reactions and mobility of electrode materials. In situ Raman analyses of deposits in the envelopes and ampoules, supported by an extensive database of the Raman spectra of lamp materials, and ex situ X-ray diffraction (XRD) analyses of refractory deposits to confirm independently the Raman assignments, have demonstrated that: (1) Sc metal reacts with envelope silica to produce Sc2O3 and elemental Si; (2) Sc metal in the presence of ScI3 reacts with the envelope silica to produce Sc2Si2O7; and (3) Sc metal reacts with envelope silica in the presence of NaI alone to produce Sc2O3 and not Sc2Si2O7. The results confirm and extend previous studies and demonstrate the value of Raman microscopy as a nondestructive investigative tool for lamp chemistry.

Preferred orientation of high performance carbon fibers

1992 ◽  
Vol 7 (9) ◽  
pp. 2612-2620 ◽  
Author(s):  
T. Hamada ◽  
M. Furuyama ◽  
T. Tomioka ◽  
M. Endo
Keyword(s):  
Heat Treatment ◽  
Carbon Fibers ◽  
High Performance ◽  
Preferred Orientation ◽  
Fiber Axis ◽  
Precursor Fiber ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Clear Peak

The preferred orientation of polyacrylnitrile (PAN)-based carbon fibers, mesophase pitch-derived carbon fibers, and pitch precursor fibers was studied by using x-ray diffraction technique. The half width at half maximum (HWHM) intensity of the φ scan x-ray diffraction profiles of these fibers was a minimum at around 2θ = 26°. The result implies that a crystallite with a larger coherence length of crystallite size Lc(002) is better aligned along the fiber axis than that with a smaller Lc(002) in these fibers. Further, θ-2θ scan profiles depending on φ showed that a better aligned crystallite possesses a larger Lc(002) than a misaligned one. Lc(002) of a significantly misoriented crystallite remained constant at about 2 nm even after heat-treatment, though Lc(002) of a well-aligned crystallite was easily changed by heat-treatment for both PAN and pitch-based fibers. The pitch precursor fiber exhibited a clear peak at about 2θ = 7° in the θ-2θ profile and unusual ° scan profiles for 2θ around 7°, which were explained by assuming columnar structures formed by molecule stacking along the c-axis with periodic arrangements of the columns perpendicular to the c-axis. The periodic column stacking structure observed in the pitch precursor fiber was also detected in pitch-based carbon fibers heat-treated at lower temperatures.

Preparation of TiO2 Coatings on Carbon Fibers

2022 ◽  
Vol 1049 ◽  
pp. 117-123
Author(s):  
Rida Gallyamova ◽  
Rustam Safiullin ◽  
Vladimir Dokichev ◽  
Fanil F. Musin
Keyword(s):  
Carbon Fibers ◽  
Sol Gel ◽  
Fiber Surface ◽  
Rutile Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Oxidation Resistance ◽  
Heat Treated ◽  
Burnout Rate ◽  
Average Size

Carbon fibers have been TiO2 coated. Previously, the carbon fiber surface has been heat-treated to remove the sizing. The TiO2 layer has been formed on the fiber surface using the sol-gel technique by immersion in a solution. After coating, the samples have been dried at room temperature and annealed at 500 °C in air for 30 minutes. The phase composition of the coating obtained has been studied using X-ray diffraction. X-ray diffraction analysis of the coating and sol has shown that the rutile phase and the average size of TiO2 crystallites grow with an increase in the annealing temperature. The results of studying TiO2 coating antioxidative properties within 500-800 °C are given. Studying the morphology of the TiO2 coating on the fiber surface and the burnout rate (weight change) have shown that the coating exhibits good oxidation resistance up to 600 °C.

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