Search results for "Lithium perchlorate"
showing 5 items of 5 documents
The role of lithium, perchlorate and water during electrochemical processes in poly(3,4-ethylenedioxythiophene) films in LiClO4 aqueous solutions
2021
Abstract Thin films of poly(3,4-ethylendioxythiophene) (PEDOT) were electrochemically deposited on gold electrodes in aqueous media. The role of perchlorate, lithium, and water during the charge/discharge of PEDOT films was investigated by cyclic voltammetry together with EQCM, vis − NIR spectroscopy, and acoustic impedance, also by means of ac-electrogravimetry in a 0.1 M LiCl O 4 aqueous solutions. In this way, it has been possible to correlate the electrical, mass, color and electromechanical properties changes during the electrochemical reactions of this polymer. Both, hydrated lithium cations and perchlorate anions can act as counterions during the electrochemical reactions, however, a…
Electrochemical Growth and Physico-Chemical Characterization in Organic Medium of Nb2O5 Thin Films
2008
Investigations about the energetics and the electrical properties of niobium thin film, electrochemically grown, were performed in an organic solution of acetonitrile and lithium perchlorate. The study of the energetics of the Nb2O5/organic solution interface was performed by means of a non-destructive optical technique, photocurrent spectroscopy. By means of this technique, it was possible estimating the value of the flat band potential and locating conduction and valence band. A more cathodic value of flat band potential in respect with acidic solution was found in organic medium. From impedance spectra, the electrical circuit that gives best fitting values is constituted by two resistanc…
Effect of Lithium Perchlorate on the Kinetics of the Anionic Polymerization of Methyl Methacrylate in Tetrahydrofuran
1999
The kinetics of the anionic polymerization of methyl methacrylate in the presence of lithium perchlorate (LiClO 4 ) are investigated in THF using 1,1-diphenylhexyllithium as initiator in a flow-tube reactor between -30 and 0 °C. The rate constants of propagation determined in the presence of LiClO 4 are lower than those obtained in the absence of the salt, similar to the effect observed for LiCl. For propagation, the reaction order with respect to active center concentration is found to be 0.5 in both cases, which indicates that LiClO 4 does not effectively perturb the aggregation of the enolate ion pair. The formation of various mixed aggregates is proposed. The polydispersity index of the…
An electrochemical quartz crystal microbalance study of lithium insertion into thin films of tungsten trioxide I. Modeling of the ionic insertion mec…
1995
A theoretical description of the mechanism of lithium insertion into amorphous thin films of tungsten trioxide (a-WO3) prepared by thermal vacuum evaporation of WO3 powder is presented. The model developed is based on the experimental results obtained by chronoamperometry and ac impedance spectroscopy associated with electrochemical quartz crystal microbalance (EQCM). The electrode mass change and the current flowing through the electrochemical cell during cathodic polarization are simulta neously recorded. As expected, it can be observed that the insertion process is associated with a gain of mass of the inserted electrode at long times (t > 1 s). On the other hand at short times (t < 1 s)…
An electrochemical quartz crystal microbalance study of lithium insertion into thin films of tungsten trioxide II. Experimental results and compariso…
1995
Abstract Lithium insertion into amorphous thin films of tungsten trioxide (a-WO 3 ) prepared by thermal vacuum evaporation of WO 3 powder has been studied experimentally by chronoamperometry, cyclic voltammetry and ac impedance spectroscopy associated with electrochemical quartz crystal microbalance (EQCM). During cathodic polarization of the electrode and at short times two antagonistic processes occur. One is a non faradaic process and is associated with the expulsion of anions from the electrode surface under the effect of the electric field built in the electrolyte when a potential difference is imposed between the electrodes. The other one is the faradaic insertion of non-solvated lith…