scholarly journals Synthesis of Nano-Crystalline LiNdxMn2-xO4Powder by Novel Cam-Microwave Assisted Sol-Gel Method

2007 ◽  
Vol 4 (4) ◽  
pp. 487-495 ◽  
Author(s):  
K. Suryakala ◽  
R. Venckatesh

With the advancement of nanotechnology, there is an interest in the replacement of conventional materials by nanomaterials. There is a reasonable chance that as the active mass of electrode for lithium batteries is comprised of smaller particles, they will perform better in terms of capacity, power, rate capability and stability. LiMn2O4is inexpensive material but it shows rather poor cyclic performance. The electrochemical performance of spinel type LiMn2O4has been effectively improved with doping of Nd the “bottom–up” approach of LiMn2O4and LiNdxMn2-xO4(x = 0.1, 0.2, 0.3 and 0.4) synthesized by citric acid modified microwave assisted sol-gel method. LiMn2O4has been synthesized from nitrates and acetates. Citric acid was added as a complexing agent and acryl amide acts as a gelling agent. This technique offers better homogeneity, preferred surface morphology, reduced heat-treatment conditions, sub-micron sized particles and better crystallinity. The structure and the electrochemical performances of the samples are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, cyclic voltammetry and charge-discharge testing. XRD data shows both samples exhibit the same pure spinel phase. Nano crystalline LiNd0.3Mn1.7O4sample has a smaller morphology including small particle size and the homogeneous particle distribution compared to the other compositions.

2015 ◽  
Vol 740 ◽  
pp. 3-6
Author(s):  
Guo Yuan Cheng ◽  
Xing Hua Fu ◽  
Xin Jin ◽  
Wen Hong Tao ◽  
Yu Qin Qiang

KNN-BF piezoelectric ceramics synthesized by sol-gel method in this experiment. By controlling bismuth and iron content in the system to study effects of them. We selected citric acid as metal chelator and ethylene glycol as esterification agent. PH maintained 5-6 during preparation of the sol. Sintering temperature of ceramic selected 1100°C. Preparation ceramics under these conditions and comparative analysis, the structure of ceramics is single perovskite and shap of crystals are square block. With the increase of x, properties of ceramics firstly increases and then decreases: d33, εr, Qm, Kpreaching the maximum, values of them were 136pC/N, 630(f =1KHz), 212, 0.41 respectively; dielectric loss to minimum is 0.07(f =1KHz); at this point, ceramics had best performance.


1991 ◽  
Vol 30 (Part 2, No. 6A) ◽  
pp. L1052-L1055 ◽  
Author(s):  
Kumi Okuwada ◽  
Shin-ichi Nakamura ◽  
Motomasa Imai ◽  
Keiichi Kakuno

2018 ◽  
Vol 41 (3-4) ◽  
pp. 53-62 ◽  
Author(s):  
Behnaz Lahijani ◽  
Kambiz Hedayati ◽  
Mojtaba Goodarzi

Abstract In this work, the PbFe12O19 nanoparticles were prepared by the simple and optimized precipitation method with different organic surfactants and capping agents. In the next step, the TiO2 nanoparticles were synthesized using the sol-gel method. At the final step, the PbFe12O19-TiO2 nanocomposites were prepared via the sol-gel method. The effect of the precipitating agent on the morphology and particle size of the products was investigated. The prepared products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The results obtained by the vibrating sample magnetometer show the magnetic properties of the ferrite nanostructures. The photocatalytic effect of the PbFe12O19-TiO2 nanocomposite on the elimination of the azo dyes (acid black, acid violet and acid blue) under ultraviolet light irradiation was evaluated. The results indicate that the prepared nanocomposites have acceptable magnetic and photocatalytic performance.


2014 ◽  
Vol 91 ◽  
pp. 19-23
Author(s):  
Plamen Pashev ◽  
Rositsa Raykova ◽  
Yancho Hristov ◽  
Bogdan Bogdanov

The study presented deal with preparation of batches of the system Y-Ba-Cu-O using sol-gel method and citric acid as precursor. Batches with particle size of 100 nm containing each of the phases Y123 and Y211 were prepared. The stoichiometric amounts of Y, Ba and Cu oxides were dissolved in 65% HNO3 until clear blue solution was observed under heating to 80 ̊С. The nitrate solutions obtained were neutralized to pH = 6 with 25% solution of NH3 (p.a.), then С6Н8О7 was added as the gels obtained were thermally treated. The transformation processes taking place under change of temperature were studied by IR, XRD, DTA and SEM.


2018 ◽  
Vol 735 ◽  
pp. 945-949 ◽  
Author(s):  
Shuai Zheng ◽  
Jiangying Wang ◽  
Jingji Zhang ◽  
Hongliang Ge ◽  
Zhi Chen ◽  
...  

2020 ◽  
Vol 44 (23) ◽  
pp. 9813-9821
Author(s):  
H. Issaoui ◽  
A. Benali ◽  
M. Bejar ◽  
E. Dhahri ◽  
R. F. Santos ◽  
...  

Perovskite (La0.8Ca0.2)1−xBixFeO3 compounds were synthesized by sol–gel method using the citric acid route and sintered at 800 °C and 900 °C. LCBFO 800 series has the smallest size of crystallites, a larger magnetization and a smaller Curie temperature.


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