Ionics
Films of hexanoyl chitosan-based polymer electrolyte were prepared by the technique of solution casting. The effect of plasticizer on the transport properties of hexanoyl chitosan:lithium trifluoromethanesulfonate (LiCF3SO3) electrolytes have been investigated. The plasticizer used was ethylene carbonate (EC). The highest room temperature conductivity achieved in the EC-plasticized hexanoyl chitosan-based...
A polymer blend electrolyte based on polyvinyl alcohol (PVA) and polyacrylonitrile (PAN) was prepared by a simple solvent casting technique in different compositions. The ionic conductivity of polymer blend electrolytes was investigated by varying the PAN content in the PVA matrix. The ionic conductivity of polymer blend electrolyte increased with the increase of PAN content. The effect of lithium...
The activity in the field of computer-aided optimum design in engineering of electrochemical gas sensors has been increasing steadily over the last decade. A vast range of models exist today, varying in complexity and in the number of assumptions employed. However, the emphasis in a majority of the models has been either on the transport processes or on the electrochemical processes. This manuscript...
We present the synthesis, characterization, and electrode behavior of LiNi0.5Mn1.5O4 spinels prepared by the wet-chemical method via citrate precursors. The phase evolution was studied as a function of nickel substitution and upon intercalation and deintercalation of Li ions. Characterization methods include X-ray diffraction, SEM, Raman, Fourier transform infrared, superconducting quantum interference...
An ion layer gas reaction dip coating process for the deposition of tungsten trioxide has been developed. Thin films of electrochromic tungsten trioxide with thicknesses of up to 150 nm were prepared. The films were found to be microcrystalline by X-ray diffraction analysis. The growth rate of the films was measured by profilometry. The chemical diffusion coefficient of lithium was investigated as...
Proton-conducting glasses doped with heteropolyacid were synthesized, and their structural characterization has been investigated. The structural analysis shows that proton-conducting glasses have been thermally, chemically, and mechanically stable. The average pore size (∼2–3 nm) and specific surface areas were investigated by the BET method. The phosphotungstic acid based on glasses as electrolyte...
This paper reviews the various classes of ionic liquids (ILs) in view of their established and expected applications in advanced electrochemical devices, such as lithium batteries, fuel cells, and supercapacitors. In this respect, particular attention is devoted to aprotic and protic ILs, with a related discussion in terms of their thermal and transport properties. In addition, the role in the electrochemical...
Ionic conductivity and chemical diffusion coefficient have been studied for superionic polycrystalline Cu1.75Se copper selenide within the temperature interval 300–500 K. An increase in ionic conductivity with an grain size increase is observed. In our opinion, this fact is caused by lower activation energy for the bulk diffusion than that for the grain boundary diffusion.
Oxygen permeation measurements were carried out on La0.8Sr0.2Ga0.75Mg0.15Co0.10O3±δ specimens of different thickness at temperatures between 673 and 1173 K under various gradients of oxygen partial pressure. Simultaneously, the open circuit cell voltage was measured. It was shown that the investigated compositions were characterized by a high oxygen permeation rate, and, consequently, by a high electronic...
TiO2-coated LiNi1/3Co1/3Mn1/3O2 materials were prepared by the hydrolyzation of Ti(OBu)4. The impact of TiO2 coating on the structure and electrochemical properties of LiNi1/3Co1/3Mn1/3O2 was investigated using X-ray diffraction, scanning electron microscope, and charge–discharge tests. The results indicated that TiO2 coating did not affect the lattice of LiNi1/3Co1/3Mn1/3O2, but exhibited obvious...
Yttria-stabilized zirconia (YSZ)-based composite electrolytes were produced by mixture and firing of the base electrolyte, namely with silica, and silica and lanthanum oxide, to study the impact of presence and formation of new phases on the electrical performance of the composite materials. Combined information obtained from structural, microstructural, and electrical characterization confirmed the...
The present work considers the gas/solid equilibration kinetics for nonstoichiometric oxides in general and TiO2 in particular. Several criteria that must be addressed in the determination of the chemical diffusion coefficient are outlined. The equilibration kinetics during oxidation and reduction are considered in terms of rate controlling reactions, including (1) bulk diffusion, (2) surface reaction,...
A nickel–metal hydride secondary battery is discharged intermittently through a switch of 30 s on/30 s off mode via an external load R r. The discharge current i g is measured during switch-on and an open-circuit voltage V oc during switch-off. In the course of discharge run, i g drops at some time by depletion of an active material within the positive electrode. The pulse shapes of i g and V oc in...
A new multilayered electrochemical cell for NOx decomposition was prepared. The cell demonstrated good characteristics at moderate temperatures (350–450 °C) and possessed much higher selectivity with respect to NOx decomposition than previous one. It was found that the “crossover” process from high selective regime to the normal regime depends on the chemical composition of the catalytic electrode.
The chemical shifts of 7Li MAS nuclear magnetic resonance spectra in La4/3−yLi3yTi2O6 (LLTO) showed negative values and decreased with increasing lithium concentration. The chemical shifts were interpreted by Pople’s theory in which the 7Li chemical shifts were due to the local paramagnetic currents of the closest oxygen ions. Lattice parameters and coordination of oxygen were obtained by Rietveld...
Ion-conducting solvent-free solid polymer electrolytes based on polyethylene oxide (PEO) complexed with sodium ferric tetrafluoride (NaFeF4) were prepared using a solution casting technique. The complexation of the films was investigated through X-ray diffraction and Fourier transform infrared spectroscopic studies. Measurements of DC conductivity in the temperature range 300–370 K and the transference...
New sulfide glasses in the Li2S–Sb2S3–P2S5 system have been prepared by classical quenching technique where glassy domain remains up to 50% molar addition of Li2S and electrical conductivities have been determined by impedance spectroscopy. Room temperature DC conductivity vs Li2S content exhibits two regions implying different conductivity mechanisms. The compositions of low lithium content presented...
Investigation of the electrical properties of polymer–clay nanocomposites is important in the development of nanoelectronic devices. These nanocomposites may be prepared by intercalating suitable monomers within interlayer spaces of expanding layered clay materials, followed by in situ polymerization. We made use of this approach to prepare montmorillonite–polyaniline nanocomposites by ion-exchanging...
MG30 is natural rubber grafted with 30% poly(methyl methacrylate). Gel polymer electrolytes containing MG30–LiCF3SO3–X (X = propylene carbonate, ethylene carbonate) are prepared by solution casting technique. The polymer–salt complexes were investigated using Fourier-transformed infrared. The ionic conductivity of the electrolytes are determined by the ac impedance studies over the temperature range...
This paper introduces a novel in situ method for monitoring electrode reactions in lithium-ion batteries parallel to the electrochemical experiment (in situ electrochemical environmental scanning electron microscopy). Alloy and alloy/carbon composite electrodes suffer from large volume changes followed by cracking and loss of electronic contact of the particles. The measurement setup and the cell...