Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Electrochromic Properties of Peroxopolytungstic Acid Thin Films (1998)
    Springer
    Journal of sol gel science and technology 13 (1998), S. 923-927 
    Details
    ISSN: 1573-4846
    Keywords: electrochromics ; peroxopolytungstic acid ; film
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Electrochromic thin films have been deposited from peroxopolytungstic acid aqueous solutions. These solutions are obtained via the dissolution of tungstic acid in hydrogen peroxide. The nature and properties of the films depend on the drying procedure. Amorphous films are formed upon fast drying. They exhibit good electrochromic properties but have to be heat treated in order to become insoluble. Crystalline films are formed upon slow drying. Their electrochromic properties are not very good but better amorphous or crystalline films are then obtained after a thermal treatment above 200°C. In both cases, the reversibility of lithium insertion is not good during the first cycles but improve significantly upon cycling. This should be due to the electrochemical reduction of peroxo groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008631525347
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Structural Studies During Gelation of WO3 Investigated by In-situ Raman Spectroscopy (2000)
    Springer
    Journal of sol gel science and technology 18 (2000), S. 199-206 
    Details
    ISSN: 1573-4846
    Keywords: tungsten oxide ; sol-gel ; Raman spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In the course of the preparation of WO3 by sol-gel technique we have studied kinetics of its synthesis and the structural changes during gelation. In-situ Raman scattering spectra were obtained for a series of samples during the transition from aqueous solution to gel. The changes in the Raman features were monitored as a function of time during gelation. The removal of water molecules affects the symmetric W=O stretching mode. The Raman spectrum of a gelified sample shows peaks attributed to the O–W–O bending mode and the disappearance of the high-frequency mode attributed to polyanionic species. After two days the gelified sample became a precipitated material, which exhibited the Raman spectrum of a crystalline tungsten oxide hydrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008775318802
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Characterization and Electrochemical Studies of LiMn2O4 Cathode Materials Prepared by Combustion Method (1999)
    Springer
    Journal of electroceramics 3 (1999), S. 433-441 
    Details
    ISSN: 1573-8663
    Keywords: LiMn2O4 spinel ; Raman ; FTIR ; XPS ; lithium-ion batteries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A combustion method using urea as a fuel has been developed for the synthesis of the spinel LiMn2O4 around 500°C. Physical features of the products were identified by X-ray photoelectron spectroscopy, X-ray diffractometry, Raman scattering and FTIR spectroscopy. Cells were fabricated with Li//LiMn2O4 and C//LiMn2O4 in nonaqueous organic electrolyte and their performances were studied. A kinetic profile for diffusion of Li ions in the composite matrix was developed and tested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009982301437
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Influence of the synthesis method on the structural and electrochemical properties of LiCo1−yNiyO2 oxides (2000)
    Springer
    Ionics 6 (2000), S. 434-441 
    Details
    ISSN: 1862-0760
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract To optimize the LiCo1−yNiyO2 cathode materials, we have systematically studied the influence of synthesis parameters on their electrochemical behavior using powders synthesized by different wet-chemistry methods (combustion and sol-gel). It is found that the thermal decomposition behavior plays an important role on the intrinsic properties of the powders. Products were studied in details. Characterizations include compositional analysis, morphology, crystallographic structure, and local structure for LiCo1−yNiyO2 materials calcined at 800 °C. A comparison of the different methods is given for the synthesis of LiCo1−yNiyO2 cathode materials. It is found that well-structured oxides with uniformly sized ultrafine particles are obtained using the sol-gel method assisted by succinic acid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02374164
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Electrochromic properties of tungsten oxides synthesized from aqueous solutions (1997)
    Springer
    Ionics 3 (1997), S. 104-109 
    Details
    ISSN: 1862-0760
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Tungsten oxides are known to exhibit interesting electrochemical properties. Ion insertion (Li+, H+) within the oxide network is highly reversible. It leads to a blue coloration and WO3 thin films can be used as electrochromic layers in display devices or smart windows. Tungsten oxide thin films can be conveniently deposited from aqueous solutions of tungstic acid. However polytungstic acids are not stable and tend to precipitate into hydrated tungsten oxide WO3⋅2H2O. The condensation of polytungstic species can be chemically controlled by adding foreign ions in the solution. Precipitation is no more observed in the presence of H2O2. Peroxopolytungstic acids are formed in which chelating [O2]2− ligands prevent the formation of an oxide network. Such solutions are specially convenient for the deposition of optically transparent thin films. Mixed oxides WO3-MoO3 are obtained when condensation is performed in the presence of Mo6+ cations. This paper shows how the condensation of tungstic acid can be chemically controlled and describes the electrochemical properties of the films deposited from such solutions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02375531
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Studies of the local structure in LixNi0.7Co0.3O2 (0.5≤x≤1.0) cathode materials (1998)
    Springer
    Ionics 4 (1998), S. 106-113 
    Details
    ISSN: 1862-0760
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Among the LixNi1−yCoyO2 system, LiNi0.7Co0.3O2 is being considered one of the best cathode materials due to its small volume cell expansion upon charge-discharge cycling. In order to study the modifications of structural and physical properties occurring in the cathode materials during charge, different LixNi0.7Co0.3O2 samples (0.5 ≥ x ≥ 1.0) were prepared by electrochemical lithium deintercalation in non-aqueous cells. During the first charge of the Li//LixNi0.7Co0.3O2 cell, the structural change in the cathode lattice was followed by both x-ray powder diffraction and FTIR spectroscopy at room temperature. A good correlation is found between XRD data and the local environment of the host lattice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02375787
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Lithium intercalation in α′-NayV2O5 synthesized via the hydrothermal route (1998)
    Springer
    Ionics 4 (1998), S. 227-233 
    Details
    ISSN: 1862-0760
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Vanadium bronzes NayV2O5 are synthesized via the hydrothermal route from a mixture of V2O5 and NaOH in the presence of a reducing agent. Fine crystalline powders made of needle-like particles are obtained that exhibit the layered structure typical of the α′-NayV2O5 phase (y≈1). Electron delocalization arises from a hopping process of unpaired electrons between V4+ and V5+. Alkaline cations are intercalated between the oxide layers and discharge curves show that up to one Li+ ion per vanadium can be reversibly inserted between the [V2O5] layers in the 3.3–0.5 V range. Chemical diffusion coefficient of Li ions in LixNaV2O5 is found to be dependent on the degree of intercalation. D+ varies from 1×10−10 up to 5×10−10 cm2/s for 0≤×≤2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02375950
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Frequency dispersion in electrochromic devices and conducting polymer electrodes: A generalized transmission line approach (1999)
    Springer
    Ionics 5 (1999), S. 44-51 
    Details
    ISSN: 1862-0760
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract This paper is concerned with the characterization of thin film electrodes by electrochemical impedance. The main problem addressed is the quantitative description of microscopic processes giving rise to frequency dispersion. Models are suggested for the identification and analysis of transport and capacitive processes occurring either at the bulk of the diffusion layer, or at its boundaries. Suitable representations in terms of transmission lines with generalized and distributed elements are provided. The main result is the possibility of the models to provide hints on the origin of the frequency dispersion and therefore correlating the response to structural elements. An application of the method is examined by analysis of impedance measurements of a WO3 electrochromic layer and a conducting polymer electrode.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02375902
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Structural properties of LiNi1−yCoyO2 (0≤y≤1) synthesized by wet chemistry via malic acid-assisted technique (1999)
    Springer
    Ionics 5 (1999), S. 345-350 
    Details
    ISSN: 1862-0760
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have synthesized LiNi1−yCoyO2 powders by a sol-gel method using malic acid as a chelating agent. The dependence of physico-chemical properties of the powders (crystallinity, lattice constants, grain size) has been investigated by changing the malic acid quantity and the calcination temperature for the different LiNi1−yCoyO2 oxides in the composition range 0 ≤ y ≤1. Structural studies show that a layered single phase was obtained for the y values 0.2 ≤ y ≤ 1.0. The local cationic environment has been studied by Raman and FTIR spectroscopy. Using acid-assisted LiNi1−yCoyO2 powders (with compositions y=0.8 and y=0.6) calcined at 800 °C, Li//LiNi1−yCoyO2 cells were assembled and tested by galvanostatic titration. These cells had an initial capacity of 140 mAh/g in the voltage range 2.8-4.2 V and showed attractive charge-discharge profiles upon cycling.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02375998
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Anomalous electrical behavior in ferromagnetic La1−xBaxCoO3−δ materials (0〈x≤0.50) (1999)
    Springer
    Ionics 5 (1999), S. 213-219 
    Details
    ISSN: 1862-0760
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We prepared in this work La1−xBaxCoO3−δ (0〈x≤0.50) compounds using the nitrate decomposition method, and focus in the study of the transport properties of the ferromagnetic compounds (x〉0.15, Tc≈200 K) in the temperature range 77 K≤T≤300 K. We find that while for x〈0.20 these materials show semiconducting behavior, their electrical conduction being dominated by small-polaron holes, for x〉0.20 they show metallic behavior for T〉100 K, with a transition to semiconducting behavior being observed for T ≤ 100 K. For x=0.20, small changes in the oxygen stoichiometry of the samples - due to slight variations in the thermal treatments - greatly affect the transport properties of the materials that can show either two metal-insulator transitions as the temperature increases or a semiconducting behavior. Very interestingly all these ferromagnetic samples are very sensitive to the polarity of the applied electrical current, and display peculiar “diodic” behaviors. All these observations are explained on the basis of an inhomogeneous electronic structure in the Ba-doped cobalt perovskites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02375842
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...