scholarly journals Silicon/polypyrrole nanocomposite wrapped with graphene for lithium ion anodes

MRS Advances ◽  
2017 ◽  
Vol 2 (54) ◽  
pp. 3323-3327 ◽  
Author(s):  
Changling Li ◽  
Chueh Liu ◽  
Zafer Mutlu ◽  
Yiran Yan ◽  
Kazi Ahmed ◽  
...  

ABSTRACTHerein, silicon nanoparticles (SiNPs) are coated with conducting hydrogel and wrapped with reduced graphene oxide (rGO) sheets via a facile and scalable solution-based sol-gel process. The in-situ polymerized polypyrrole (PPy) hydrogel forms an interconnected three-dimensional (3D) fiber matrix. Amine and hydroxyl groups from the hydrogel assist the encapsulation of the SiNPs through hydrogen bonding. The electro-conductive PPy fiber network and the wrapping of rGO offer efficient electron and ion transport pathways. The PPy/SiNPs/rGO electrodes can produce highly reversible capacities of 1312, 1285 and 1066 mAh g-1 at 100, 250 and 500 cycles at a current density of 2.1 A g-1, respectively.

2012 ◽  
Vol 535-537 ◽  
pp. 1529-1533
Author(s):  
Qing Ling Liao ◽  
Li Ming Zeng ◽  
Xuan Ke Li

The modified phenolic resin was synthesized by sol-gel process using in-situ formed nanosized silica. The improved phenolic resin was characterized by IR and TG-DTA analyses .The results show that the interaction between SiO2 nanoparticles and phenolic resin lead to the decrease of concentration of phenolic hydroxyl groups, and introduce the impurity atom Si to the phenolic resin molecule chain, which promotes the heat resistance and stability of phenolic resin. The physicochemical property analyses show that the magnesite-carbon brick using this modified phenolic resin as binder possesses a low apparent porosity and a high bulk density and compression strength.


2020 ◽  
Vol 59 (1) ◽  
pp. 477-487 ◽  
Author(s):  
Zhuang Liu ◽  
Haiyang Fu ◽  
Bo Gao ◽  
Yixuan Wang ◽  
Kui Li ◽  
...  

AbstractThis paper studies in-situ synthesis of Fe2O3/reduced graphene oxide (rGO) anode materials by different hydrothermal process.Scanning Electron Microscopy (SEM) analysis has found that different processes can control the morphology of graphene and Fe2O3. The morphologies of Fe2O3 prepared by the hydrothermal in-situ and oleic acid-assisted hydrothermal in-situ methods are mainly composed of fine spheres, while PVP assists The thermal in-situ law presents porous ellipsoids. Graphene exhibits typical folds and small lumps. X-ray diffraction analysis (XRD) analysis results show that Fe2O3/reduced graphene oxide (rGO) is generated in different ways. Also, the material has good crystallinity, and the crystal form of the iron oxide has not been changed after adding GO. It has been reduced, and a characteristic peak appears around 25°, indicating that a large amount of reduced graphene exists. The results of the electrochemical performance tests have found that the active materials prepared in different processes have different effects on the cycle performance of lithium ion batteries. By comprehensive comparison for these three processes, the electro-chemical performance of the Fe2O3/rGO prepared by the oleic acid-assisted hydrothermal method is best.


CrystEngComm ◽  
2016 ◽  
Vol 18 (14) ◽  
pp. 2532-2540 ◽  
Author(s):  
Shuang Li ◽  
Qian Xu ◽  
Evan Uchaker ◽  
Xi Cao ◽  
Guozhong Cao

Amorphous, pseudohexagonal and orthorhombic Nb2O5 nanoparticles were synthesized by sol–gel process. The material characteristics and electrochemical performance of these polymorphs were compared.


2016 ◽  
Vol 284 ◽  
pp. 1-6 ◽  
Author(s):  
Takashi Teranishi ◽  
Yuki Ishii ◽  
Hidetaka Hayashi ◽  
Akira Kishimoto

1998 ◽  
Vol 519 ◽  
Author(s):  
Y. Yan ◽  
Z. Duan ◽  
D.-G. Chen ◽  
S. Ray Chaudhuri

AbstractThe insoluble, strongly hydrogen bonded organic pigment of 3,6-bis-(4-chlorphenyl)-l,4- diketopyrrolo [3,4-c] pyrrole was transiently blocked by adding carbamate groups, and consequently incorporated into organic-inorganic hybrid matrices by a sol-gel process. The homo- (pigment-pigment) and hetero-intermolecular (pigment-matrix) interactions were found to control both the assembly and dispersion of pigment molecules in the hybrid coating films. A weaker interaction between matrices and pigment molecules results in aggregation of the carbamate pigment in the methyl-silicate films. A stronger interaction forms a homogenous dispersion and coloration of the phenyl-silicate films. The as-prepared methyl- and phenylsilicate films doped with the organic pigment were distinguished by a morphology change and a blue (hypsochromic) shift in absorption from 550 to 460 nm. Thermal treatment can remove the carbamate groups and in-situ form the organic pigment in the hybrid films.


Author(s):  
Atef Y. Shenouda ◽  
M. M. S. Sanad

Li2NixFe1−xSiO4 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) samples were prepared by sol–gel process. The crystal structure of prepared samples of Li2NixFe1−xSiO4 was characterized by XRD. The different crystallographic parameters such as crystallite size and lattice cell parameters have been calculated. Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) investigations were carried out explaining the morphology and function groups of the synthesized samples. Furthermore, electrochemical impedance spectra (EIS) measurements are applied. The obtained results indicated that the highest conductivity is achieved for Li2Ni0.4Fe0.6SiO4 electrode compound. It was observed that Li/Li2Ni0.4Fe0.6SiO4 battery has initial discharge capacity of 164 mAh g−1 at 0.1 C rate. The cycle life performance of all Li2NixFe1−xSiO4 batteries was ranged between 100 and 156 mAh g−1 with coulombic efficiency range between 70.9% and 93.9%.


2018 ◽  
Vol 3 (43) ◽  
pp. 12108-12112 ◽  
Author(s):  
Xiaoqing Liu ◽  
Dan Zhang ◽  
Guangshe Li ◽  
Chenglin Xue ◽  
Junfang Ding ◽  
...  

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