scholarly journals Anisotropic Vanadium Oxide Nanostructured Host Matrices for Lithium Ion Intercalation

2007 ◽  
Vol 2007 ◽  
pp. 1-5 ◽  
Author(s):  
C. O'Dwyer ◽  
V. Lavayen ◽  
M. A. Santa Ana ◽  
E. Benavente ◽  
G. González ◽  
...  
Keyword(s):  
Vanadium Oxide ◽  
Sol Gel ◽  
Lithium Ion ◽  
High Volume ◽  
Synthetic Methods ◽  
Degree Of Crystallinity ◽  
The Individual ◽  
Low Dimensional ◽  
Ion Intercalation ◽  
High Degree

We report on unique high-volume low-dimensional V2O5-based turbostratic nanostructures, prepared using sol-gel synthetic methods from V2O5⋅nH2O xerogels. Electrochemical intercalation of Li+ to form Li0.65V2O5 resulted in a maximum measured charge capacity of 1225 mAh g−1 as the β-LixV2O5 phase. Conductivities of the order of 10−3 S cm−1 were found on compressed-nanotube parallelepipedal samples, which exhibit an anisotropy factor of 70 at room temperature by preferential alignment of the nanotubes. The improved electrochemical properties observed in novel vanadium oxide nanostructured arrays are attributed to the increased volumetric density for ion intercalation, shorter diffusion paths to the intercalation sites, and a high degree of crystallinity of the individual nanotubular host structures.

Multicomponent 5V Cathodes for Li-ion Batteries

2008 ◽  
Vol 1127 ◽  
Author(s):  
Malgorzata K. Gulbinska ◽  
Boris Ravdel ◽  
Svetlana Trebukhova ◽  
Brian N. Hult ◽  
Sanjeev Mukerjee
Keyword(s):  
Electrode Materials ◽  
Sol Gel ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Synthetic Methods ◽  
X Ray Diffraction ◽  
Mechanical Mixing ◽  
Li Ion ◽  
Ion Intercalation ◽  
Synthesized Materials

ABSTRACTIn this study, the multicomponent electrode approach was used in an attempt to simultaneously improve the cell's specific energy values by shifting the cathode's voltage up to the 5V-region, combined with the increased specific capacity via addition of the second electrode component. The electrode materials were prepared by variety of synthetic methods (e.g. solid state, sol-gel, mechanical mixing etc.) and tested for lithium-ion intercalation properties. Structural properties and morphology of synthesized materials were characterized by X-ray diffraction (XRD) methods. The prospective 5V cathode materials were investigated as cathodes in the cells with lithium-metal counter electrode.

A Novel Composite Li3V2(PO4)3∥Li2NaV2(PO4)3/C as Cathode Material for Li-Ion Batteries

2018 ◽  
Vol 71 (7) ◽  
pp. 497
Author(s):  
Lingfang Li ◽  
Changling Fan ◽  
Jiaxing Yang
Keyword(s):  
Electrochemical Performance ◽  
Metal Ion ◽  
Coulombic Efficiency ◽  
Sol Gel ◽  
Lithium Ion ◽  
Composite Cathode ◽  
X Ray Diffraction ◽  
Li Ion ◽  
Ion Intercalation ◽  
Charge Discharge

A novel composite cathode for lithium ion batteries, Li3V2(PO4)3‖Li2NaV2(PO4)3/C, was synthesized by a sol-gel method. Cetyltrimethylammonium bromide (CTAB) was used as a surfactant while polyvinylidene difluoride (PVDF) was the carbon source. X-ray diffraction (XRD) and Raman results showed that the components of this composite are monoclinic Li3V2(PO4)3, rhombohedral Li2NaV2(PO4)3 and an amorphous carbon-coating. Four potential plateaus occur at the charge/discharge curves and the longest plateau is observed at a potential of 3.8/3.7 V. Therefore, the alkali metal ion intercalation and deintercalation mostly occur at this potential, which is different to that observed for Li3V2(PO4)3. In addition to the stable working potential, this composite also possesses an outstanding electrochemical performance. The sample containing 8.32 % carbon content delivers a capacity of 119 mAh g−1 at 0.2 C rate and 87 mAh g−1 at 12 C. After 50 charge/discharge cycles at 1 C, a coulombic efficiency of 98.4 % is maintained. This enhancement of the electrochemical performance could be attributed to the synergistic effect between monoclinic Li3V2(PO4)3 and rhombohedral Li2NaV2(PO4)3.

Nanostructured Vanadium Oxide Electrodes for Enhanced Lithium-Ion Intercalation

2006 ◽  
Vol 16 (9) ◽  
pp. 1133-1144 ◽  
Author(s):  
Y. Wang ◽  
K. Takahashi ◽  
K. H. Lee ◽  
G. Z. Cao
Keyword(s):  
Vanadium Oxide ◽  
Lithium Ion ◽  
Oxide Electrodes ◽  
Ion Intercalation

scholarly journals Properties, production methods and use of tin nanoxide

Surface ◽  
2020 ◽  
Vol 12(27) ◽  
pp. 193-230
Author(s):  
А. R. Zheleznyak ◽  
◽  
О. М. Bakalinska ◽  
А. V. Brichka ◽  
G. O. Kalenyuk ◽  
...  
Keyword(s):  
Tin Oxide ◽  
Oxygen Vacancies ◽  
Crystal Surface ◽  
Sno2 Nanoparticles ◽  
Sol Gel ◽  
Lithium Ion ◽  
Structural Features ◽  
Degree Of Crystallinity ◽  
Wide Range ◽  
Metastable Compounds

The prevalence of tin compounds, economic affordability and non-toxicity determine its wide range of applications. Modern scientific literature on the properties, methods of preparation and application of tin nanooxide is analyzes in review. Its main characteristics and structural features are described. The ability of tin cations to be in two oxidation states, the ease of reduction of Sn+4 to Sn+2 and reverse oxidation, determines the redox properties of the SnO2 surface. In addition to stable oxides Sn4+ and Sn2,+ the existence of a homologous series of Snn+1O2n metastable compounds is assumed. It is proved that four-coordinated Sn+2 cations on the SnO2 surface can coexist only with oxygen vacancies in the immediate environment. Such cationic sites have the properties of strong Lewis acids and are highly reactive. Computer simulation of the SnO2 crystal surface allows us to propose a number of catalytic activity of SnO2 surfaces: (110) < (001) < (100) < (101). Preparation methods and synthesis parameters (nature and type of precursor, stabilizing agent and solvent, duration and temperature of the reaction, pH of the reaction mixture, etc.) determine the physicochemical properties of nanoparticles (shape, size, morphology and degree of crystallinity). The main (sol-gel, precipitation and coprecipitation, CVD, spray pyrolysis, hydrothermal, “green”) and less common (detonation, electric discharge) methods of nano-SnO2 obtaining are analyzed in the work. A variety of methods of synthesis and conditions makes it possible to obtain SnO2 nanoparticles with desired properties, which determine the activity of tin oxide in redox reactions, namely: nanosize and morphology of particles with prevalence of the most reactive faces - (100) і (101). Among the methods that do not require complex hardware design, one can dwell on the methods of sol-gel, "green" and coprecipitation. Tin oxide is traditionally used as an abrasive for polishing metal, glass and ceramic products. The transition to nanosized particles allows this material to reversibly absorb and release oxygen, which has determined its use in the design of gas-sensitive and biosensors, the creation of solar cells, fuel cells, lithium-ion batteries, oxidation catalysts, transparent and photoconductors. The multivalence and the presence of oxygen vacancies on the surface of tin oxide nanoparticles, the ease and speed of penetration into the cell membrane give nano-SnO2 properties of medicinal preparations, which makes it possible to use it in biomedical technologies for the treatment of diseases associated with oxidative stress lesions. The size, concentration of nanoparticles and modification of their surface are the key factors of influence, which usually intensify the antimicrobial, antibacterial, antitumor and antioxidant activity of the material.

scholarly journals Synthesis and characterization of Cu doped chromium oxide (Cr2O3) thin films

2019 ◽  
Vol 38 (2019) ◽  
pp. 806-812 ◽  
Author(s):  
Ahlam Zekaik ◽  
Hadj Benhebal ◽  
Bedhiaf Benrabah
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Visible Region ◽  
Dip Coating ◽  
Nyquist Plot ◽  
Degree Of Crystallinity ◽  
Cu Doping ◽  
Parallel Circuit ◽  
High Degree

AbstractCu-doped Cr2O3 thin films were deposited onto glass substrate by the sol–gel dip-coating (SGDC) process using dopant values of 0, 3, 6, 9 and 12%. The Chromium (III) Nitrate Nonahydrate [Cr(NO3)3·9H2O] was used as a Cr source, whilst for the dopant, the corresponding nitrate (Cu(NO3)2) was used. The crystal structure, as well as the optical and electrical properties were examined. XRD data showed that the films with a high degree of crystallinity were rhombohedral Cr2O3 phase. The crystallite size reduces with increase in Cu doping proportion. The AFM results indicate a decrease in the surface roughness of the doped Cr2O3: Cu thin films. The UV-Vis spectra of the Cu doped-Cr2O3 films showed high transparency in the visible region. The optical band gap of Cr2O3 thin films decreases with increasing in Cu doping rate. The Nyquist plot shows that the equivalent circuit of Cu doped-Cr2O3 films is a parallel circuit RpCp. As the concentration of Cu increases, Resistance RP regresses while capacitance Cp increases.

Lithium Ion Intercalation Performance of Porous Laminal Titanium Dioxides Synthesized by Sol−Gel Process

2009 ◽  
Vol 21 (3) ◽  
pp. 499-505 ◽  
Author(s):  
Min-Chiao Tsai ◽  
Jian-Chia Chang ◽  
Hwo-Shuenn Sheu ◽  
Hsin-Tien Chiu ◽  
Chi-Young Lee
Keyword(s):  
Sol Gel ◽  
Lithium Ion ◽  
Sol Gel Process ◽  
Titanium Dioxides ◽  
Ion Intercalation

scholarly journals Doped Bi2Te3 nano-structured semiconductors obtained by ultrasonically assisted hydrothermal method

2013 ◽  
Vol 11 (10) ◽  
pp. 1599-1605 ◽  
Author(s):  
Stefan Novaconi ◽  
Paulina Vlazan ◽  
Iosif Malaescu ◽  
Iulia Badea ◽  
Ioan Grozescu ◽  
...  
Keyword(s):  
Particle Size ◽  
Hydrothermal Method ◽  
Degree Of Crystallinity ◽  
Nanocrystalline Powders ◽  
Electrical Measurements ◽  
Force Microscopy ◽  
Treatment Conditions ◽  
Low Dimensional ◽  
High Degree ◽  
Shape And Size

AbstractNanocrystalline powders of doped Bi2Te3, with Ag (S1 sample), Sb (S2 sample), Sn (S3 sample) ions with different morphology and particle size 30–50 nm were prepared by a ultrasonically assisted hydrothermal method in alkaline aqueous solution with different concentration of NaBH4 as reducing agent at 200°C for 3 hours and 80% fill degree of autoclave. The influence of dopants and hydrothermal treatment conditions on the formation features, phase composition, particle size, morphology and properties of the products were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy and electrical measurements. This paper reports a comparative study regarding the dopants influence to the shape and size of nano-structured thermoelectric materials. It was found that hydrothermal processing results in formation of low dimensional dispersion of doped Bi2Te3 nanostructures with desired shape and size and high degree of crystallinity with typical semiconductor behavior.

Semiology of the Pain Syndrome - Identifying the Ideal Methods of Locoregional Anesthesia Based on Their Rationale and Features

2017 ◽  
Vol 68 (10) ◽  
pp. 2373-2377
Author(s):  
Mihaela Monica Scutariu ◽  
Vlad Danila ◽  
Corina Ciupilan ◽  
Oana Elena Ciurcanu
Keyword(s):  
Maxillofacial Surgery ◽  
Essential Element ◽  
Pain Syndrome ◽  
Oral And Maxillofacial Surgery ◽  
Structuring Element ◽  
Technical Accuracy ◽  
Locoregional Anesthesia ◽  
Special Approach ◽  
The Individual ◽  
High Degree

Anesthesia and the degree of control over the perception of pain depends on the personality of the individual, the socio-economic conditions, potential previous painful experiences and, last but not least, on fatigue and fear of the dentist. The perception of pain in patients is closely connected to their mental state. Pain is defined as a sensation of discomfort, with wide variations, both in quality and intensity, for different people in seemingly identical conditions; an unpleasant sensitive and emotional phenomena connected to the threat of a wound or caused in the tissues or described in the terms of this disease. The essential element of any type of anesthesia is analgesia, an effect which in some cases cannot be achived, due to the patient�s particularities or the physician�s lack of experience in anesthesia. Locoregional anesthesia (LRA) represents the blocking of the nociceptive sensitive and sympathetic autonomic afferents as well as that of motor efferents at the level of peripheral nerves� axons, by means of local anesthetic. To achieve the set purpose, we carried out a study on a representative human sample comprised of 10.123 patients treated in the Oral and Maxillofacial Surgery Clinic (Ambulatory) from the County Clinic Emergency Hospital St. Spiridon Iasi, between 01.01.2015-31.12.2016. The reason for the exclusion of certain categories of patients in the reseach was: the patients with a special conditions background require individual pre-anesthesia schemes, personalised for the nature of the pre-existing general condition, which must be further approved by the attending specialist physician : cardiologist, internist, diabetologist; children under 18 years old, with a high degree of anxiety; a high precentage of elderly patients, over 60 years old, possess a combination of general issues, thus requiring a special approach. The thoroughness lying at the core of the anesthetic practice, most especially the safegurading of a technical accuracy in the performance of anesthesia [12,], instead of improvisations, the lack of anatomical and stomatological training in general and the resulting inefficiency as such, is the underlying in-depth structuring element of this paper.

scholarly journals Territories of state-led aquaculture risk management: Thailand’s Plang Yai program

2020 ◽  
pp. 239965442096524
Author(s):  
Mariska JM Bottema ◽  
Simon R Bush ◽  
Peter Oosterveer
Keyword(s):  
Risk Management ◽  
Policy Instruments ◽  
Spatially Explicit ◽  
Financial Risks ◽  
Shared Resources ◽  
Globalizing World ◽  
Farmer Behavior ◽  
Key Policy ◽  
The Individual ◽  
High Degree

The Thai aquaculture sector faces a range of production, market and financial risks that extend beyond the private space of farms to include public spaces and shared resources. The Thai state has attempted to manage these shared risks through its Plang Yai (or ‘Big Area’) agricultural extension program. Using the lens of territorialization, this paper investigates how, through the Plang Yai program, risk management is institutionalized through spatially explicit forms of collaboration amongst farmers and between farmers and (non-)state actors. We focus on how four key policy instruments brought together under Plang Yai delimited multiple territories of risk management over shrimp and tilapia production in Chantaburi and Chonburi provinces. Our findings demonstrate how these policy instruments address risks through dissimilar but overlapping territories that are selectively biased toward facilitating the individual management of production risks, whilst enabling both the individual and collective management of market and financial risks. This raises questions about the suitability of addressing aquaculture risks by controlling farmer behavior through state-led designation of singular, spatially explicit areas. The findings also indicate the multiple roles of the state in territorializing risk management, providing a high degree of flexibility, which is especially valuable in landscapes shared by many users, connected to (global) value chains and facing diverse risks. In doing so we demonstrate that understanding the territorialization of production landscapes in a globalizing world requires a dynamic approach recognizing the multiplicity of territories that emerge in risk management processes.

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