Synthesis of Spherical LiFePO4/C Composites as Cathode Material of Lithium-Ion Batteries by a Novel Glucose Assisted Hydrothermal Method

2013 ◽  
Vol 787 ◽  
pp. 58-64 ◽  
Author(s):  
Xiang Feng Li ◽  
Zhao Zhang ◽  
Fang Liu ◽  
Shu Ping Zheng
Keyword(s):  
Hydrothermal Method ◽  
Raw Materials ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
High Discharge ◽  
X Ray ◽  
High Discharge Capacity ◽  
Optimal Sample ◽  
Structure Morphology

The LiFePO4/C composites with different morphology are synthesized by a novel glucose assisted hydrothermal method at various glucose concentrations (from 0 to 0.25mol/L) and the insoluble lithium source Li2CO3, (NH4)2Fe (SO4)2·6H2O and (NH4)2HPO4(n (Li):n (Fe):n (P)=1:1:1) are used as raw materials. The structure, morphology, thermal performance and electrochemical properties of the synthesized composites are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), thermogravimetry/differential scanning calorimetry (TG-DSC), galvanostatic charge/discharge tests and cyclic voltammetry (CV). The results show that the LiFePO4/C synthesized with 0.125mol/L glucose has the relatively small particles size (0.1~0.5μm) and the well spherical morphology. The optimal sample exhibits a high discharge capacity of 160.0mAh/g at the first cycle and exhibits a good reversibility and stability in CV tests.

scholarly journals Synthesis of Li4Ti5O12/V2O5 Nanocomposites for Lithium-ion Batteries by a One-pot co-precipitation Method

2021 ◽  
Author(s):  
liu zhenjie ◽  
Yudai Huang ◽  
xingchao Wang ◽  
Yue Zhang ◽  
juan Ding ◽  
...  
Keyword(s):  
Lithium Ion ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
One Pot ◽  
High Discharge ◽  
X Ray ◽  
High Discharge Capacity ◽  
Transmission Electron ◽  
Co Precipitation ◽  
Nano Size

Abstract Li4Ti5O12/V2O5 nanocomposites were synthesized by a one-pot co-precipitation method. The structure and morphology of the as-prepared materials were analyzed by X-ray diffraction and transmission electron microscopy. The results show that Li4Ti5O12/V2O5 composites with different nano size were successfully synthesized. The Li4Ti5O12/V2O5 sample (2 wt.% V2O5 addition of Li4Ti5O12) keep at a high discharge capacity of 169.9 mAh g− 1 after 150 cycles at 1 C. The existence of the V2O5 reduces the size of Li4Ti5O12, which improve the electrochemical activity of the sample.

Synthesis and Properties of Thermotropic Liquid Crystalline Polyesters with Flexible Polymethylene Spacer

2010 ◽  
Vol 428-429 ◽  
pp. 126-131
Author(s):  
Wei Zhong Lu ◽  
Chun Wei ◽  
Qui Shan Gao
Keyword(s):  
Optical Microscopy ◽  
Liquid Crystalline ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Structure Morphology ◽  
Temperature Ranges ◽  
Ft Ir ◽  
Diffraction Peaks ◽  
Ubbelohde Viscometer

Polymethylene bis(p-hydroxybenzoates) were prepared from methyl p-hydroxybenzoate and different diols by melted transesterification reaction. Three liquid crystalline polyesters were synthesized from terephthaloyl dichloride and polymethylene bis(p-hydroxybenzoates). Its structure, morphology and properties were characterized by Ubbelohde viscometer, Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimetry (DSC), polarized optical microscopy (POM) with a hot stage, and wide-angle X-ray diffraction (WAXD). Results indicated that the intrinsic viscosities were between 0.088 and 0.210 dL/g. Optical microscopy showed that the TLCP has a highly threaded liquid crystalline texture and a high birefringent schlieren texture character of nematic phase and has wider mesophase temperature ranges for all polyesters. DSC analysis were found that the melting point (Tm), isotropic temperature (Ti) of TLCPs decreased and the temperature range of the liquid crystalline phase became wider with increased number of methylene spacers in the polyester. The WAXD results showed that TLCPs owned two strong diffraction peaks at 2θ near 19° and 23°.

scholarly journals Synthesis and Crystal Structure of the Bioinorganic Complex [Sb(Hedta)]·2H2O

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Di Li ◽  
Guo-Qing Zhong
Keyword(s):  
Crystal Structure ◽  
Ethylenediaminetetraacetic Acid ◽  
Raw Materials ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Cell Parameters ◽  
Composition And Structure ◽  
Decomposition Processes ◽  
Distorted Trigonal Bipyramid

The antimony(III) complex [Sb(Hedta)]·2H2O was synthesized with ethylenediaminetetraacetic acid (H4edta) and antimonous oxide as main raw materials in aqueous solution. The composition and structure of the complex were characterized by elemental analysis, infrared spectra, single crystal X-ray diffraction, X-ray powder diffraction, thermogravimetry, and differential scanning calorimetry. The crystal structure of the antimony(III) complex belongs to orthorhombic system, space group Pna2(1), with cell parameters ofa=18.4823(18) Å,b=10.9408(12) Å,c=7.3671(5) Å,V=1489.7(2) Å3,Z=4, andDc=1.993 g cm−3. The Sb(III) ion is five-coordinated by two amido N atoms and three carboxyl O atoms from a single Hedta3−ligand, forming a distorted trigonal bipyramid geometry. The thermal decomposition processes of the complex include dehydration, oxidation, and pyrolysis of the ligand, and the last residue is Sb2O3at the temperature of 570°C.

Synthesis and Characterization of New Polyurethane Adhesives

2006 ◽  
Vol 514-516 ◽  
pp. 843-847 ◽  
Author(s):  
Cristina Borges Correia ◽  
João C. Bordado
Keyword(s):  
Raw Materials ◽  
Impact Resistance ◽  
Inert Atmosphere ◽  
Stray Field ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Polyurethane Adhesives ◽  
Dimer Acids

Polyurethane adhesives provide excellent flexibility, impact resistance and durability. Polyurethanes are formed through the reaction of an isocyanate component with polyether or polyester polyols or other active hydrogen compounds. This paper refers to polyurethane adhesives made from polyester polyols with long aliphatic chains (up to 36 carbon atoms) and MDI (diphenylmethane-4,4’-diisocyanate). The polyester polyols have been made from dimer acids obtained from renewable sources and short chain diols. The polyols that were used presented different degrees of unsaturation. The influence of the different raw materials in the adhesives performance is studied. The polyurethanes were produced by reaction between quasi-stoichiometric quantities of polyol and MDI, at several temperatures. The reaction was carried under inert atmosphere and at temperatures below 100°C. Performance of the adhesives was tested by carrying adhesion, hardness and water absorption tests. Characterization of both the polyester polyols and polyurethane adhesives was carried by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Magnetic Nuclear Resonance (NMR), X-Ray Diffraction (WAXD), Scanning RMN Imaging of 1H of Stray- Field b (MRI) and Brookfield viscometry.

Effect of thermal treatment on the mechanical and viscoelastic response of polypropylenes incorporating a β nucleating agent

2018 ◽  
Vol 51 (6) ◽  
pp. 562-579 ◽  
Author(s):  
K Belkouicem ◽  
A Benarab ◽  
R Krache ◽  
R Benavente ◽  
E Pérez ◽  
...  
Keyword(s):  
Young Modulus ◽  
Nucleating Agent ◽  
Thermal Treatments ◽  
Mechanical Parameters ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Good Balance ◽  
X Ray ◽  
Structure Morphology ◽  
Ultimate Properties

The influence of two thermal treatments on the structure, morphology, and ultimate properties exhibited by isotactic polypropylene (iPP), synthesized by conventional Ziegler–Natta iPP (Z-iPP) or metallocene iPP (m-iPP) catalysts, has been investigated in the present work. Novelty of this research consisted in the incorporation of a β nucleating agent in two different contents to the m-iPP. Results attained are compared with those found in the Z-iPP and important differences are observed. Differential scanning calorimetry and X-ray diffraction experiments revealed that coexistence of different crystalline lattices took place depending on the type of iPP: β and α forms were found in the β nucleated Z-iPP specimens, whereas α, β, and γ polymorphs could be developed in the m-iPP with nucleating agent. On the other hand, the iPP glass transition temperature ( Tg) did not exhibit a significant change because of the addition of β nucleant, as deduced from Dynamic Mechanical Thermal Analysis (DMTA) analysis. Moreover, the size and shape of the iPP spherulites was totally changed by the presence of the β agent. This nucleant promoted the formation of smaller spherulites in a greater amount, as demonstrated by optical microscopy. Concerning the mechanical parameters, microhardness, MH, and Young modulus, E, values were in the fast crystallized samples lower than those presented by their slowly cooled counterparts. A good balance in properties was seen for the slowly crystallized m-iPP that incorporated a 5 wt% content in β nucleating agent, this fact being ascribed to the coexistence of the three α, β, and γ polymorphs.

LiFePO4/C Cathode Materials Prepared by One-Step Fast Carbothermal Method Using Fe2O3 as Raw Materials

2013 ◽  
Vol 773 ◽  
pp. 709-713
Author(s):  
Bao Hua Rong ◽  
Yan Wen Lu ◽  
Qing Lin Chen ◽  
Kun Tang ◽  
Xue Wen Liu ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Raw Materials ◽  
Synthesis Temperature ◽  
Cycle Performance ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Sintering Atmosphere ◽  
X Ray ◽  
One Step ◽  
Carbothermal Method

LiFePO4/C was successfully synthesized by one-step solid-state reaction using Fe2O3, LiH2PO4 and sucrose as raw materials. The effect of synthesis temperature and sintering atmosphere on the electrochemical performance were investigated. LiFePO4/C materials were characterized by differential scanning calorimetry and thermogravimetry, X-ray diffraction, scanning electron microscopy and XPS. The results show that the synthesis temperature between 750 °C and 800 °C were appropriate and the reductive ambience can enhance the electrochemical performance effectively especially at high rates. The precursor calcined at 750°C for 5h in a N2+5%H2 atmosphere exhibited the highest discharge capacity of 155 mAh/g at 0.1C and 141 mAh/g at 1C and showed the best cycle performance.

scholarly journals Synthesis of BaTiO3 Nanoparticles via Hydrothermal Method

2017 ◽  
Vol 268 ◽  
pp. 172-176 ◽  
Author(s):  
Nurul Norfarina Hasbullah ◽  
Oon Jew Lee ◽  
Josephine Liew Ying Chyi ◽  
Soo Kien Chen ◽  
Zainal Abidin Talib
Keyword(s):  
Electron Microscope ◽  
Hydrothermal Method ◽  
Transmission Electron Microscope ◽  
Hydrothermal Process ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Average Size ◽  
Tga And Dsc

In this work, BaTiO3 nanoparticles were synthesized through hydrothermal method. The powder obtained from the hydrothermal process (as-synthesized powder) was calcined at 1000 °C. The phase formation and morphology of the as-synthesized and calcined powders were studied using X-ray diffraction (XRD), thermogravimetric (TGA) and differential scanning calorimetry (DSC) analyzer, and transmission electron microscope (TEM). The XRD data showed that the as-synthesized powder is partially amorphous. Upon calcining the powder at 1000 °C, highly crystalline BaTiO3 with tetragonal structure was obtained. As shown by TGA and DSC analysis, the precursor powder was completely transformed into BaTiO3 at 1000 °C. The presence of BaCO3 as an impurity phase in the powder is due to the lack of Ba2+ / Ti3+/4+. Transmission electron microscope images showed that the particle size of the as-synthesized powder increased after calcination due to crystal growth. In addition, nanocubes with the average size of around 11.66 nm were obtained as a result of the calcination compared to the ellipsoid like particles of the as-synthesized powder.

Rod-Like LiMn2O4 Evolved from Porous Spherical Flower-Like Carbonate Precursors

2013 ◽  
Vol 291-294 ◽  
pp. 771-777
Author(s):  
Hua Li Zhu ◽  
Ming Xu ◽  
Zhao Yong Chen
Keyword(s):  
Lithium Ion ◽  
Particle Sizes ◽  
Scanning Electron Micrographs ◽  
X Ray Diffraction ◽  
Spinel Limn2o4 ◽  
Scanning Calorimetry ◽  
Capacity Retention ◽  
X Ray ◽  
Initial Discharge ◽  
Discharge Test

Spinel LiMn2O4 was prepared by solid state reaction from composite carbonate precursors Li2CO3 and MnCO3, which were obtained by coprecipitation method. The physicochemical properties of spinel LiMn2O4and its precursor were investigated by simultaneous thermogravimetry-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), scanning electron micrographs (SEM) and galvanostatic charge-discharge test, respectively. The carbonate precursors demonstrate the porous spherical flower-like morphology, and spinel LiMn2O4shows the rod or rod clusters-like one with different particle sizes. The spinel LiMn2O4prepared from composite carbonate precursors delivers an initial discharge capacity of 115 mAh/g with excellent capacity retention, indicating an attractive application in the high-power lithium-ion batteries.

scholarly journals Nano-CL-20/HMX Cocrystal Explosive for Significantly Reduced Mechanical Sensitivity

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Chongwei An ◽  
Hequn Li ◽  
Baoyun Ye ◽  
Jingyu Wang
Keyword(s):  
Spray Drying ◽  
Raw Materials ◽  
Drop Height ◽  
Drying Method ◽  
X Ray Diffraction ◽  
Mechanical Sensitivity ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Friction Sensitivity ◽  
Scanning Electron

Spray drying method was used to prepare cocrystals of hexanitrohexaazaisowurtzitane (CL-20) and cyclotetramethylene tetranitramine (HMX). Raw materials and cocrystals were characterized using scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, Raman spectroscopy, and Fourier transform infrared spectroscopy. Impact and friction sensitivity of cocrystals were tested and analyzed. Results show that, after preparation by spray drying method, microparticles were spherical in shape and 0.5–5 µm in size. Particles formed aggregates of numerous tiny plate-like cocrystals, whereas CL-20/HMX cocrystals had thicknesses of below 100 nm. Cocrystals were formed by C–H⋯O bonding between –NO2 (CL-20) and –CH2– (HMX). Nanococrystal explosives exhibited drop height of 47.3 cm, and friction demonstrated explosion probability of 64%. Compared with raw HMX, cocrystals displayed significantly reduced mechanical sensitivity.

Glass-Ceramics Obtained from Sewage Sludge and its Characteristics Affected by Alkalinity

2014 ◽  
Vol 937 ◽  
pp. 70-73
Author(s):  
Di Wu ◽  
Jun Zhang ◽  
Xing Wang Wen ◽  
Hui Ling Liu
Keyword(s):  
Sewage Sludge ◽  
Raw Materials ◽  
Glass Ceramics ◽  
Chemical Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Sludge Disposal ◽  
Physical And Chemical ◽  
And Chemical Properties

Sewage sludge was tested as component for producing glass-ceramics with the addition of analytic reagent CaO to solve the sewage sludge disposal problems. The effect of alkalinity (Ak=mCaO/mSiO2) on the characteristics of the glass-ceramics was investigated. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were used to investigate thermal behavior and crystalline phase of the samples. It was found that the degree and characteristics of crystals in vitrified sludge significantly correlate to the alkalinity of the raw materials. The glass-ceramics with Ak = 0.36 possessed the best physical and chemical properties.

Sign in / Sign up

Export Citation Format

Share Document