scholarly journals Promising Cathode Material for Lithium Power Sources LaFe0.5Cr0.5O3

2017 ◽  
Vol 18 (4) ◽  
pp. 444-448
Author(s):  
I. P. Yaremiy ◽  
M. L. Mokhnatskyi ◽  
L. V. Mokhnatska ◽  
S. I. Yaremiy ◽  
A. I. Kachmar

Nanoscale powders of LaFe0.5Cr0.5O3 with perovskite structure were synthesized by the sol-gel combustion method in this work. From X-rays phase analysis obtained material consisted of one phase LaFe0.5Cr0.5O3 (space group P m -3 m). The average size of RCS of test material is 21 nm. The specific surface area is 14 m2/g. The average particle size is 63.7 nm by approximation that particles form is spherical. Nanoscale powders of LaFe0.5Cr0.5O3were tested as cathode material for lithium power sources. The cathode material demonstrates the specific power capacity of 571 A•h/kg when the discharge of the source is up to 0.5V.

2017 ◽  
Vol 17 (01n02) ◽  
pp. 1760012
Author(s):  
S. Gowreesan ◽  
A. Ruban Kumar

The scope of the present work is in enhancing the particle size, and dielectric properties of Mg-substituted Cobalt ferrites nanoparticles prepared by sol–gel auto combustion method. The different ratios of Mg-substituted Co Ferrites (Co[Formula: see text]MgxFe2O4([Formula: see text], 0.05, 0.10, 0.15, 0.20 and 0.30)) are calcinated at 850[Formula: see text]C. The synthesized nanoparticles were characterized by powder XRD, FTIR, FE-SEM, EDX techniques and dielectric behavior. The structural parameters were confirmed from powder XRD and the average particle size is obtained from 39 to 67 nm due to the substitution of Mg[Formula: see text] which was calculated by Debye Scherrer’s formula. FE-SEM showed the surface morphology of the different ratio of the sample. The dielectric loss has measured the frequency range of 50[Formula: see text]Hz–5[Formula: see text]MHz. From electrical modulus, conductivity relaxation and thermal activation of charge carriers has been discussed.


2018 ◽  
Vol 24 (8) ◽  
pp. 5801-5804
Author(s):  
K. N. Shravana Kumara ◽  
H. P Nagaswarupa ◽  
K. R. Vishnu Mahesh ◽  
M Mylarappa ◽  
S. C Prashantha ◽  
...  

The objective of this work is mainly focused on green synthesis and characterization of MgO nanoparticles by low temperature solution combustion method. The Murraya koenigii (Curry leaves) was used as a reducing agent (as fuel). The average size and crystallinity of nano MgO particles are analyzed by X-ray Diffraction method (PXRD) and accurate morphology was studied using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). From XRD, shows that average particle size of MgO is 40 nm. The synthesized MgO particles used as an efficient catalyst shows rapid color removal and reduction in the concentration of dyes.


Author(s):  
Changsheng Ding ◽  
Hongfei Lin ◽  
Kazuhisa Sato ◽  
Toshiyuki Hashida

La0.8Sr0.2Co0.8Fe0.2O3 (LSCF) nanopowders, which are being investigated as a promising cathode material for low-temperature solid oxide fuel cells (SOFCs), were synthesized by citric acid gel combustion method. The LSCF nanopowders synthesized at 700°C are single perovskite phases and have an average particle size of less than 30 nm. In order to evaluate the use of the synthesized LSCF nanopowders as cathode material of low-temperature SOFCs, anode-supported SOFCs were fabricated from the synthesized LSCF nanopowders and tested in the conditions of humidified hydrogen for anode and oxygen for cathode. The anode-supported single cell with the LSCF cathode sintered at 700°C showed high electrical performance with the maximum power density of 771 mW cm−2 at 600°C. The results show that the synthesized LSCF nanopowders are suitable to be applied as cathode material for low-temperature SOFCs.


2020 ◽  
Vol 21 (2) ◽  
pp. 219-226
Author(s):  
B. K. Ostafiychuk ◽  
H. M. Kolkovska ◽  
I. P. Yaremiy ◽  
B. I. Rachiy ◽  
P. I. Kolkovskyi ◽  
...  

In this work, the perovskite LaMnO3 material has been prepared based on the sol-gel process of synthesis with the participation of combustion. According to the X-ray phase analysis, it was determined that the obtained material consists of LaMnO3 one phase (space group Pm-3m). Nevertheless, it has been determined that the average size of the coherent scattering region of the obtained material is about 24 nm. Moreover, the average particle size is 40-60 nm in case the approximation that the particles are spherical shape. Thus, it has been determined that the specific surface area of the material is 42.1 m2/g. The electrochemical investigations have been performed using nanosized LaMnO3 powder as a cathode material for electrochemical capacitors. The LaMnO3 material under research showed a specific capacity of 40 F/g at a discharge of up to 1V.


2017 ◽  
Vol 31 (15) ◽  
pp. 1750175 ◽  
Author(s):  
Gh. H. Khorrami ◽  
M. Mousavi ◽  
M. Dowran

In this paper, potassium sodium niobate (KNN) nanopowders were successfully obtained by sol–gel combustion method. According to thermogravimetric analysis (TGA) results, the produced xerogel was calcined at 500[Formula: see text]C, 600[Formula: see text]C, and 700[Formula: see text]C to obtain KNN powders. The structural and optical properties of the prepared powders were studied using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, transmission electron microscopy (TEM), and UV–vis spectroscopy. The XRD patterns indicated formation of orthorhombic KNN samples. The Scherrer formula and size–strain plot (SSP) method were employed to calculate crystallite size and lattice strain of the KNN powders. The TEM image revealed that the average particle size of the prepared samples is about 30 nm and they have cubic shape. The optical band gap energy of the samples was calculated using UV–vis absorbance spectra of the samples along with Tauc relation.


2021 ◽  
Vol 12 (3) ◽  
pp. 3066-3075

Herein is a new procedure to synthesize lanthanum oxide (La2O3) nanoparticles, which is eco-friendly and simple. The La2O3 nanoparticles were prepared by sol-gel method using modification in time of stirring, type of PEG, and temperature of the reaction. Scherer's formula was used to estimate the average crystallite of La2O3 nanoparticle size from X-ray diffraction peaks of powder. The measured average particle size of La2O3 nanoparticles using the major signals of the X-ray diffraction spectrum after calcination was 37 nm. Fourier Transform Infrared Spectroscopy technique was done to analyze the chemical structure of synthesized materials. The surface morphology of obtained nanoparticles was also studied by SEM and AFM techniques. Thermal gravimetric analysis was investigated by Thermogravimetric analysis (TGA) to confirm the thermal stability of synthesized nanoparticles.


Author(s):  
Ramesh N. Taikar ◽  
Sadanand R. Sarve ◽  
Disha T. Yele ◽  
Deepak R. Taikar ◽  
Kalpana R. Nagde

Nano Ni-Zn ferrite with composition Ni 0.6 Zn 0.4 Fe2O4 is prepared by using sol-gel auto-combustion method with citric acid as a fuel. The structural properties of synthesized nano-ferrite is characterized by powder X-ray diffraction (XRD) technique while the electrical properties have been studied using two probe method. The X-ray diffraction study confirms that, there is a formation of single-phase cubic spinel with most intense peak at [311] having lattice constant of 8.3585 A0 and the average particle size is found to be 45.63 nm. In addition to this, the electrical resistivity of Ni-Zn Ferrite decreases with increase in temperature which exhibits semiconductor nature.


2016 ◽  
Vol 15 (05n06) ◽  
pp. 1660002 ◽  
Author(s):  
V. Kavitha ◽  
P. S. Ramesh ◽  
D. Geetha

Copper doped Titanium dioxide TiO2 nanoparticles were synthesized by sol–gel method using titanium tetraisopropoxide and copper sulfate as precursors. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), UV-Visible spectroscopy (UV-Vis), Photoluminesce spectroscopy (PL) and atomic force microscopy (AFM). XRD analysis confirms the formation of anatase titanium dioxide and average particle size was 35[Formula: see text]nm. Cu– TiO2 exhibits a shift in the absorption edge toward visible spectrum. The rate of recombination and transfer behavior of the photoexcited electron–hole pairs in the semiconductors was recorded by photoluminescence. From SEM spherical shaped nanoparticles was observed. Comparing with pure TiO2 nanoparticles, Cu doped TiO2 photocatalyst exhibited enhanced photocatalytic activity under natural sunlight irradiation in the decomposition of rhodamine B aqueous solution. The maximum 97% of degradation efficiency of Rhodamine B was observed at 0.6% Cu–TiO2 within 180[Formula: see text]min. The photocatalytic efficiency of Rhodamine B of Cu doped TiO2 nanoparticle was higher than the pure TiO2, which could be attributed to the small crystallinity intense light absorption in Sunlight and narrow bandgap energy of Copper.


2021 ◽  
Author(s):  
Mahesh Gaidhane ◽  
Deepak Taikar ◽  
Pravin Gaidhane ◽  
Kalpana Nagde

Abstract Nanocrystalline α-Fe2O3 is synthesized by sol-gel technique. The prepared nanomaterial was characterized by X-ray diffraction (XRD), SEM, TEM, Fourier Transform Infrared (FTIR) spectroscopy, Vibrating Sample Magnetometry (VSM) and photoluminescence (PL) techniques. X-ray powder diffraction analysis confirmed the formation of α-Fe2O3. Electron microscopy showed spherical morphologies with an average particle size of 30-40 nm. The magnetic property of the prepared material was studied by VSM at room temperature. VSM study shows superparamagnetic nature of the synthesized nanoparticles. Photoluminescence (PL) emission spectra show intense broad emission band centered at 570 nm with 393 nm excitation indicating its usefulness for w-LED application. The CIE-chromaticity color coordinates of prepared material were calculated. The photocatalytic activity of the α-Fe2O3 nanoparticles was analyzed and the nanopowder exhibited good photocatalytic activity for the removal AO7 from its aqueous solution.


2012 ◽  
Vol 727-728 ◽  
pp. 1585-1590
Author(s):  
Neuza Evangelista ◽  
Jorge Alberto Soares Tenório ◽  
José Roberto Oliveira ◽  
Paulo R. Borges ◽  
Taiany Coura M. Ferreira

Ceramic fibers are characterized by their light weight, high degree of purity, low heat storage, low thermal conductivity, thermal shock resistance and superior corrosion resistance in high-temperature environments. In addition, they can be produced extensively in substitution to all materials used in the coating of almost all heating equipment as well as contributing to the reduction of energy consumption. Such characteristics make them ideal in the coating of distributors, mufflers, heating ovens, among others, as highly demanded by the mining and metallurgical industries, among others. After use in the process of industrial production, generated waste will lose their insulation capacity and thus require safe disposal. The present work focuses specifically on ceramic and glass wools aiming at an evaluation of their recycling prospect of incorporation into cement mortars and concrete. This residues were pulverized and displayed ~30µm average particle size. The scan electronic microscopy (SEM) presented elongated, thin and straight particles, which is very different than flocular structure of cement. The X-rays diffraction revealed amorphous structure for glass wool and crystalline structure for ceramics wool. The chemical analysis showed high concentrations of Al2O3 and silica in both residues, with higher percentage of calcium oxide in glass wool.


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