scholarly journals Eco-friendly synthesis of VO 2 with stripped pentavalent vanadium solution extracted from vanadium-bearing shale by hydrothermal process in high conversion rate

2019 ◽  
Vol 6 (2) ◽  
pp. 181116 ◽  
Author(s):  
Qian Kang ◽  
Yimin Zhang ◽  
Shenxu Bao ◽  
Guobin Zhang
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Conversion Rate ◽  
Hydrothermal Process ◽  
Lithium Ion ◽  
Raw Material ◽  
High Concentration ◽  
X Ray ◽  
Pentavalent Vanadium ◽  
High Conversion Rate

VO 2 (B) has shown excellent cathode performance in lithium batteries and become a hot research topic in recent years. A stripped vanadium solution extracted from vanadium-bearing shale containing a high concentration of vanadium and certain amounts of impurities was used as a vanadium source to synthesize VO 2 (B) by hydrothermal process. The VO 2 conversion rate can reach as high as 99.47% in a reaction time of 8 h, and this is the highest result reported. The crystalline structure and morphology of the synthesized products were characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). Furthermore, the electrochemical properties of VO 2 (B) in lithium-ion batteries were investigated. The results indicated that the VO 2 (B) has the initial specific discharge capacity of 192.0 mAh g −1 . Stripped vanadium solution is a raw material for producing V 2 O 5 and NH 4 VO 3 , which are indispensable vanadium sources in VO 2 synthesis. Therefore, synthesis of VO 2 via hydrothermal reduction by oxalic acid using stripped vanadium solution extracted from vanadium-bearing shale as a direct vanadium source is an eco-friendly, innovative and efficient method, and will have a great impact on VO 2 synthesis.

A Novel Synthesis of CaWO4:Eu3+ Flower Like Microcrystals in Ethanol/Water Mixed System and Characterization

2012 ◽  
Vol 531-532 ◽  
pp. 512-518 ◽  
Author(s):  
Ye Qing Chen ◽  
Joo Hyun Lee ◽  
Sung Wook Park ◽  
Byung Kee Moon ◽  
Byung Chun Choi ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Hydrothermal Process ◽  
Volume Ratio ◽  
Mixed System ◽  
Mixed Solution ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
High Concentration ◽  
X Ray ◽  
Xrd Patterns

In this paper, we report a successful synthesis of CaWO4:Eu3+ phosphor via an ethanol assisted hydrothermal process. X-ray diffraction (XRD) patterns, X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscope (FE-SEM) were used to investigate the growth of the products. The water and ethanol volume ratio is found to have extraordinary effect on the particle size and morphological appearance. Flower like ~ 1µm superstructures can be obtained with mixed solution of w/e of 50/50 at 120 °C hydrothermal sysnthesis for 12 h. High concentration of ethanol in aqueous solution was discovered to have a tendency in limiting the interaction between the small particles for crystallization. Temperature and time experiments were also performed to further investigate the growth mechanism of the ethanol assisted hydrothermal process. The photoluminescence properties of flower like CaWO4:Eu3+ has also been investigated.

Thickness of carbon coatings on silicon materials determined by hard X-ray photoelectron spectroscopy at multiple photon energies

2019 ◽  
Vol 26 (6) ◽  
pp. 1936-1939 ◽  
Author(s):  
Noritake Isomura ◽  
Naoko Takahashi ◽  
Satoru Kosaka ◽  
Hiroyuki Kawaura
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Secondary Electron ◽  
Lithium Ion ◽  
Cross Sectional ◽  
Carbon Coatings ◽  
X Ray ◽  
Negative Electrodes ◽  
Silicon Materials ◽  
Microscopy Images

Hard X-ray photoelectron spectroscopy at multiple photon energies is used to investigate the surface structure of carbon coatings on silicon materials destined for use as negative electrodes in lithium-ion batteries. The photoelectron intensity from the carbon coatings decreases with an increase in the kinetic energy of the photoelectron. By fitting the photoelectron intensity versus energy to numerically derived curves, the thickness and coverage of the carbon coatings can be obtained. The results are in agreement with the values suggested by the cross-sectional secondary-electron microscopy images of the carbon coatings, although the thickness should be corrected by accounting for the rectangular parallelepiped structure of the silicon material.

Synthesis of MoO3/V2O5/C Composite as Novel Anode for Li-Ion Battery Application

2020 ◽  
Vol 20 (5) ◽  
pp. 2911-2916
Author(s):  
Zhen Zhang ◽  
Xiao Chen ◽  
Guangxue Zhang ◽  
Chuanqi Feng
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Li Ion Battery ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Li Ion ◽  
Battery Application

The MoO3/V2O5/C, MoO3/C and V2O5/C are synthesized by electrospinning combined with heat treatment. These samples are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and thermogravimetric analysis (TG) techniques. The results show that sample MoO3/V2O5/C is a composite composed from MoO3, V2O5 and carbon. It takes on morphology of the nanofibers with the diameter of 200~500 nm. The TG analysis result showed that the carbon content in the composite is about 40.63%. Electrochemical properties for these samples are studied. When current density is 0.2 A g−1, the MoO3/V2O5/C could retain the specific capacity of 737.6 mAh g−1 after 200 cycles and its coulomb efficiency is 92.99%, which proves that MoO3/V2O5/C has better electrochemical performance than that of MoO3/C and V2O5/C. The EIS and linear Warburg coefficient analysis results show that the MoO3/V2O5/C has larger Li+ diffusion coefficient and superior conductivity than those of MoO3/C or V2O5/C. So MoO3/V2O5/C is a promising anode material for lithium ion battery application.

Effect of Sintering on Structural Modification and Phase Transition of Al-Substituted LLZO Electrolytes for Solid State Battery Applications

2021 ◽  
Vol 18 (3) ◽  
Author(s):  
K. Ganesh Kumar ◽  
P. Balaji Bhargav ◽  
C. Balaji ◽  
Ahmed Nafis ◽  
K. Aravinth ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Solid Electrolyte ◽  
Photoelectron Spectroscopy ◽  
Lithium Ion ◽  
Impedance Analysis ◽  
Chemical Compositions ◽  
X Ray ◽  
Reitveld Refinement ◽  
Solid State Battery

Abstract Owing to high lithium ion conductivity and good stability with lithium metal, Li7La3Zr2O12 (LLZO—a solid electrolyte) has emerged as a viable candidate for solid-state battery applications. In the current study, Al-substituted LLZO (Al-LLZO) powder is synthesized using a typical solid-state reaction. The pellets are made with the synthesized powder and are subjected to annealing for different durations and its effect on the structural properties of the Al-LLZO is investigated in detail. Reitveld refinement of the powder X-ray diffraction pattern reveals that the sintered Al-LLZO belong to the cubic system with the Ia-3d space group at room temperature. Morphology and microstructural properties of sintered powder are analyzed using field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM)/selected area electron diffraction (SAED), respectively. The FESEM image of LLZO pellets shows well-structured cubic grains spread evenly over on the surface after sintering. The chemical compositions of the sample are identified using energy dispersive X-ray analysis (EDAX). The surface chemistry of the prepared samples is examined by X-ray photoelectron spectroscopy (XPS), which states that the observed photoelectron signals from O 1s at about 531 eV and Li1s at 54.52 eV correspond to the Li-O bond in Al-LLZO. Raman spectra have been analyzed and the observed Raman peaks appearing at 299 cm−1, 393 cm−1, 492 cm−1, and 514 cm−1 were assigned to Eg, F2g, A1g, and F2g, respectively. Phase transformation from C-LLZO to the pyrochore LZO phase is noticed when the sample is sintered for 12 h at 1100 °C. The impedance analysis is carried out to measure the conductivity of the Al-LLZO pellet and is found to be 0.3 × 10−5 S cm−1, which is suitable for solid electrolyte applications in lithium ion batteries.

Large Scale Preparation of β-AgVO3 Nanowires Using a Novel Sonochemical Route

2008 ◽  
Vol 8 (6) ◽  
pp. 3203-3207 ◽  
Author(s):  
Changjie Mao ◽  
Xingcai Wu ◽  
Jun-Jie Zhu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Lithium Ion Batteries ◽  
Photoelectron Spectroscopy ◽  
Large Scale ◽  
Lithium Ion ◽  
Gravimetric Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission

A large number of β-AgVO3 nanowires with diameter of 30–60 nm, and length of 1.5–3 μm have been successfully synthesized by a simple and facile low-temperature sonochemical route. The morphologies and structures of the nanowires were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning transmission electron microscopy (SEM), and thermal gravimetric analysis (TGA). Cyclic voltammetry and charge–discharge experiments were applied to characterize the electrochemical properties of the nanowires as cathode materials for lithium-ion batteries. In the initial discharge and charge process, the as-prepared β-AgVO3 nanowires showed the initial charge and discharge capacities of 69 and 102 (mAh)/g, respectively. It is anticipated that the β-AgVO3 nanostructures are promising cathode candidates in the application of primary lithium-ion batteries.

Improved visible-light photocatalytic activity of sodium tantalum oxide via biomass-derived silk fibroin doping

2018 ◽  
Vol 89 (7) ◽  
pp. 1332-1339
Author(s):  
Yehua Sun ◽  
Yuzhuo Luo ◽  
Yaofeng Zhu ◽  
Yaqin Fu
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Silk Fibroin ◽  
Photoelectron Spectroscopy ◽  
Structural Changes ◽  
Diffuse Reflectance Spectroscopy ◽  
Hydrothermal Process ◽  
X Ray ◽  
Transmission Electron

Biomass-derived silk fibroin (SF)-doped NaTaO3 catalysts were successfully synthesized by a simple hydrothermal process using SF as the dopant. The as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) analyses. The samples were tested as photocatalysts in the degradation of methylene blue under UV and visible light. XRD results showed the monoclinic structure of NaTaO3 lacking significant structural changes after anion doping. SEM and TEM images revealed the nanocubic morphology of the samples, the crystal particle sizes of which were about 100–300 nm. The XPS spectrum showed the peak of Ta4p3&N1s, indicating the combination of N and Ta. The UV-vis DRS results of the samples revealed a cut-off edge that red shifted from 315 nm of the pure NaTaO3 to 324 nm of the SF-doped counterpart. SF doping helped narrow the band gap and rendered the prepared sample sensitive to visible light. Under UV and visible-light irradiation, SF-doped NaTaO3 exhibited higher photocatalytic activity than that the undoped compound. SF-doped NaTaO3 samples also exhibited excellent stability during the recycling photocatalytic process.

scholarly journals Binder Free SnO2-CNT Composite as Anode Material for Li-Ion Battery

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Dionne Hernandez ◽  
Frank Mendoza ◽  
Emmanuel Febus ◽  
Brad R. Weiner ◽  
Gerardo Morell
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Tin Dioxide ◽  
Composite Films ◽  
Volume Ratio ◽  
Lithium Ion ◽  
Chemical Vapor ◽  
Li Ion Battery ◽  
X Ray ◽  
Li Ion

Tin dioxide-carbon nanotube (SnO2-CNT) composite films were synthesized on copper substrates by a one-step process using hot filament chemical vapor deposition (HFCVD) with methane gas (CH4) as the carbon source. The composite structural properties enhance the surface-to-volume ratio of SnO2demonstrating a desirable electrochemical performance for a lithium-ion battery anode. The SnO2and CNT interactions were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared-attenuated total reflectance (ATR-FTIR) spectroscopy. Comprehensive analysis of the structural, chemical, and electrochemical properties reveals that the material consists of self-assembled and highly dispersed SnO2nanoparticles in CNT matrix. The process employed to develop this SnO2-CNT composite film presents a cost effective and facile way to develop anode materials for Li-ion battery technology.

scholarly journals Synthesis of a Novel In2O3-InN Bottle Nanotube Using In-Situ Partial Oxidation with Enhanced Gas Sensing Platform to Detect NO2

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 570
Author(s):  
Qiuyang Ning ◽  
Guoguang Wu ◽  
Yihui Wang ◽  
Yuanbo Sun ◽  
Wei Feng
Keyword(s):  
Electron Microscopy ◽  
Partial Oxidation ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Fast Response ◽  
High Concentration ◽  
X Ray ◽  
Sensing Platform ◽  
Lower Temperature

A brand-new gas sensor nanocomposite, In2O3-InN, was synthesized by in-situ partial oxidation of InN and presented fast response–recovery property for NO2 detecting. The structure and morphology of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray detection (EDX) analysis. The results show that the final In2O3-InN composites were composed of hexagonal type In2O3 and hexagonal type InN, which exhibited bottle nanotube structure on the relative macroscopic level. Microscopically, at the interface of In2O3 and InN, n–n hetero junction formed. Works form gas sensing property found that it is obviously that In2O3-InN got a quite stronger response, 1021, at relatively lower temperature, 100 °C, comparing to pure In2O3, 279.1 at 150 °C. After doping, the gas-sensing performance was improved. By analyzing the concentration of oxygen vacation and n–n hetero junctions mechanism, it was verified that the superiority of gas sensing properties of the In2O3-InN can be attributed to the high concentration of oxygen vacancies and the formation of n–n hetero junctions.

HYDROTHERMAL SYNTHESIS OF α-MoO3 NANORODS FOR NO2 DETECTION

2012 ◽  
Vol 11 (06) ◽  
pp. 1240044 ◽  
Author(s):  
SHOULI BAI ◽  
SONG CHEN ◽  
YUAN TIAN ◽  
RUIXIAN LUO ◽  
DIANQING LI ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Molybdenum Trioxide ◽  
Hydrothermal Process ◽  
High Sensitivity ◽  
X Ray Diffraction ◽  
Hydrothermal Temperature ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir

Thermodynamically stable molybdenum trioxide nanorods have been successfully synthesized by a simple hydrothermal process. The product exhibits high-quality, single-crystalline layered orthorhombic structure (α- MoO3 ), and aspect ratio over 20 by characterizations of X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and Fourier transform infrared (FT-IR). The growth mechanism of α- MoO3 nanorods can be understood by electroneutral and dehydration reaction, which is highly dependent on solution acidity and hydrothermal temperature. The sensing tests show that the sensor based on MoO3 nanorods exhibits high sensitivity to NO2 and is not interferred by CO and CH4 , which makes this kind sensor a competitive candidate for NO2 detection. The intrinsic sensing performance of MoO3 maybe arise from its nonstoichiometry of MoO3 owing to the presence of Mo5+ and oxygen vacancy in MoO3 lattice, which has been confirmed by X-ray photoelectron spectroscopy (XPS) analysis. The sensing mechanism of MoO3 for NO2 is also discussed.

SURFACE DECORATION OF COMMERCIAL GRAPHITE MICROSPHERES WITH SMALL Si/C MICROSPHERES AS IMPROVED ANODE MATERIALS FOR Li-ION BATTERIES

2013 ◽  
Vol 01 (04) ◽  
pp. 1340017
Author(s):  
ZAILEI ZHANG ◽  
YANHONG WANG ◽  
MEIJU ZHANG ◽  
QIANGQIANG TAN ◽  
FABING SU
Keyword(s):  
Electron Microscopy ◽  
Composite Materials ◽  
Electrochemical Performance ◽  
Photoelectron Spectroscopy ◽  
Anode Materials ◽  
Electronic Conductivity ◽  
Lithium Ion ◽  
Li Ion Batteries ◽  
X Ray ◽  
Li Ion

We report a facile chemical vapor deposition (CVD) method to grow silicon/carbon ( Si / C ) microspheres on commercial graphite microsphere (GMs) surface to prepare Si / C / GMs composite anode materials for Li -ion batteries. The CVD synthesis is conducted at 900°C using methyltrichlorosilane ( CH 3 SiCl 3) as both the Si and C precursor, which is a cheap byproduct in organosilane industry. The samples are characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermogravimetric analysis, Raman spectroscopy and X-ray photoelectron spectroscopy. It is found that the obtained Si / C / GMs composites are composed of Si nanocrystals, amorphous carbon and GMs. The CVD time significantly influences the morphology and electrochemical performance of the Si / C / GMs composite materials. The Si / C / GMs composite materials prepared at CVD condition of 900°C for 4 h possess improved electrochemical properties, showing a discharge capacity of 821.4 mAh g−1 at a rate of 50 mA g−1, and a good cycling performance (i.e., a reversible capacity of 565.2 mAh g−1 is retained after 50 cycles). The enhanced electrochemical performance is attributed to the formation of Si / C microsphere network among GMs, which increases the electronic conductivity and is able to buffer the large volume changes of Si during lithium ion insertion/extraction.

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