Proton conduction in polymer composites of PVA+H3PO4 AND PVA+H2SO4 have been investigated. The films protonated by H3PO4 show protonic conductivity between 10−6to 10−3ohm−1cm−1 depending upon the relative ratios and temperature. H2SO4 protonated PVA films also show proton conductance of almost similar magnitude. The ionic transference number has been estimated to be 0.95 for H3PO4 protonated PVA film of ratio 70:30. The frequency and temperature dependence of electrical conductivity has also been carried out. These polymer films have been used to fabricate an electrochromic cell. The colorationtime determined from response time measurement for the system “SnO2|Glass|WO3 film|PVA film|SnO2 Glass” is 2.6 sec for H3PO4 doped films and 6 seconds for H2SO4 doped films.

Water transport rates through Dow experimental polyperfluorosulfonic acid membranes were investigated by using dynamic thermogravimetry. A mathematical model was developed to describe water transport rates within the membrane. Values for the diffusion coefficient of water in membrane samples of the same equivalent weight but of three different thicknesses, 265, 4.0, and 7.0 mil, were obtained for temperatures of 60, 80, and 90° C. Results show that the diffusion coefficient of water increases with water content and temperature.

The electrical properties of poly(vinyl alcohol) complexed with phosphoric acid have been studied. It is found that the conductivity increases with the concentration of the acid, and also increases with time if the sample is exposed to the air, which is interpreted in terms of glass transition temperature. A.C. impedance measurement and polarization experiment show that this proton-conducting polymer is a promising candidate for electrochromic display. It is also found that some plasticizers, such as glycerol and ethylene-glycol are effective for improving its conductivity.

The technique of EXAFS is reviewed and its application, especially to Ca- and Zn-polymer electrolytes, is considered. The implications of the EXAFS results for the interpretation of the electrochemical properties of these electrolytes are discussed.

The topotactic insertion/extraction of lithium in layered oxides and sulfides is compared with that in the oxo- and thiospinel frameworks [M2]X4 for both the technical interest of tailoring secondary-battery cathode materials and the scientific interest of exploring narrow-band phenomena and magnetic interactions in compounds and/or phases not accessible by conventional high-temperature techniques. It is pointed out that in layered LiyCoO 2 the higher voltages accessible in oxides is compatible with the higher Li+ -ion mobilities needed in power cells, but that fast three-dimensional Li+ -ion conduction in oxides requires a framework structure such as the monoclinic/orthorhombic Fe2(MO4)3 structure stabilized by M = Mo, W, and S. The influence of the counter cation on the working redox potential is illustrated by a 0.6 eV shift in the Fe3+/2+ redox couple on going from M = Mo or W to M = S.

In contrast with amphoteric graphite layer type oxides or chalcogenides play generally the role of acceptors in intercalation reactions. Due to the more ionic character of the M-0 bonds the structural evolution of the oxides may usually be explained on hand of electrostatic considerations, or in terms of cation oxido-reduction. On contrary for the more covalent chalcogenides occupancy of energy levels in the band structure by the transferred electrons constitute a determining factor, influencing strongly not only the structural changes but also the physical properties. Similar bonding considerations account for the strong tendency of the oxides to undergo 2D → 3D transformations.

The structural, chemical and electrochemical behavior of the layered molybdate oxides Na(Li)xMo2O4 have been investigated. We found a reversible sodium intercalation process over the range of composition 0.5 < x < 1.9 for the NaxMo2O4 system with 5 single phase domains at x = 0.55, 0.9, 1-1.4, 1.6, and 1.9. We took advantage of the high mobility of sodium diffusion in this compound to exchange sodium for lithium at relatively low temperature (300°C) and to prepare crystallographically pure LixMo2O4. Electrochemical data for the Li system shows that this material, which reversibly intercalates up to 1.7 Li atoms at an average potential of 3.1 volts, is a new promising cathode material for secondary lithium batteries. The ease with which these new molybdate phases can be intercalated is not limited to the alkali metals, since we also were able to intercalate H2O molecules.

Low-dimensional solids are known to be among the best host structures to practice intercalation chemistry. Besides geometrical aspects which play an important role but are now quite well understood, this paper emphasizes the relationship between chemical reactivity and the electronic structure of the host. A special attention is paid to the nature of redox centers involved in the intercalation process and to the connection between the phase diagram and the band structure of the host material.

Polarized Raman scattering and infrared absorption measurements were carried out in FePS3 and FePSe3 as a function of temperature. Features at 700-2000 cm−1 are shown to be essentially due to transitions among the trigonal-field-split 5T2g multiplet of the Fe2+ iron and their phonon sidebands. Though the unpolarized Raman spectra are similar in both compounds, polarized spectra are markedly different. We propose a tentative model to account for this.

The synthesis methods and chemical properties of conducting chalcogenide glasses are reviewed with special emphasis on SiS2 -based glasses. Structural information obtained from DSC, FT-IR, and solid state NMR is discussed, as well as electrochemical properties, and the use of ionically conductive glasses in battery applications.

Raman scattering and IR absorption were studied in Li-intercalated MoS2 at room temperature. After intercalation, new Raman peaks were observed at low-frequency sides of the high-frequency original Raman peaks and around a rigid-layer mode. This fact indicates the formation of superlattice structure along the c-axis. An intercalation mode in which Li atoms vibrate strongly against the host lattice was observed at about 205 cm−1. Two new broad bands grow in the high-frequency region as the concentration of Li increases. The corresponding peaks were observed by IR absorption. They appears to be caused by vibrations of substitutional defects, in which the Li atoms have substituted for Mo atoms in the host lattice.

Electrochemical investigations on lithium insertion in crystalline layered chalcogenide compounds are presented. Systematic and precise studies of the voltage-composition relation were made in single crystals of InSe, In2Se3, MoS2, TiS2 and NiPS3. The stability of the intercalated phases is discussed on bases of electrochemical potential spectroscopy measurements and inverse derivative composition voltage is analysed using the lattice gas model. The chemical diffusion coefficient D and the Darken factor Kt are deduced from the galvanostatic discharge curves of the lithium-solid solution electrode cells. All parameters have been measured as a function of lithium composition.

The layered semiconductor InSe which is a potential insertion cathode for thin film batteries can be intercalated with lithium which act as donor in the host. Chemical intercalation in n-butyllithium, leads to a drastic increase of the free carrier density in the host material, InSe single crystal.

The variation of the free carrier density with intercalation shifts the plasma frequency into the region of the LO-mode vibrations and allows the observation of the plasmon-LO-phonons coupling by light scattering experiments. By varying the sample temperature, it is possible to follow the two branches of the curve ω(q) corresponding to the modes L+ and L-.

Polycrystalline InSb thin films have been prepared by the two-source electron-beam evaporation method. The InSb films have been grown on both pure Si (100) substrate and on Si (100) substrate which has been thermally oxidized to form a thin amorphous SiOx overlayer. The as-grown thin films have been heat treated under N2 atmosphere which is slightly mixed with air. A thin InOx layer is formed on the top surface of the thin film.

After heat treatment, the InSb films grown on the oxidized Si substrate shows a preferred (111) orientation. While the films grown on Si substrate do not show such preferred orientation as evidenced by the X-ray diffraction patterns.

The TEM cross sectional morphologies of the InSb film grown on oxidized Si substrate shows an ordered arrangement of the grains. While the film grown on the pure Si substrate shows a random arrangement of the grains. The film grown on the oxidized Si substrate also shows the existence of the twin boundary and an ordered arrangement of the precipitation of the second phase.

Polycrystalline InSb thin films have been prepared by the two-source thermal co-evaporation method. The InSb films have been grown on both pure Si (100) substrate and on Si (100) substrate which has been thermally oxidized to form a thin amorphous SiOx overlayer. The as-grown films have been heat treated under N2 atmosphere at different temperatures ranged from 520 to 535 C. Both as-grown films have (220) diffraction as the main peak. The heat treated films which have high mobility values show the (111) preferred orientation. For the heat treated film on oxidized Si substrate, the TEM cross sectional morphologies show the existence of the precipitaion of the second phase and the interface diffusion of InSb into the SiOx layer.

Lithium has been intercalated chemically and electrochemically in LnNb3O9 (Ln = La, Nd) perovskite-type phases and LiW3O9F which can be considered as a hexagonal tungsten bronze derivative.

The crystallographic formula of the LnNb3O9 starting material is □3/2 (Ln□1/2 )Nb3O9. In both systems, solid solutions are observed in the fir part of the intercalation reaction. While almost all perovskite cavities are filled in the neodymium phases, the higher ionic character of the La-O bonds prevents practically the Li intercalation in the □' sites.

In the LiW3O9F phase two lithium atoms can be electrochemically intercalated via a single phase mechanism. The reaction is completely reversible. For higher amounts of intercalation (x > 3), irreversible structural modifications occur.

In both systems the unit cell parameter variation is negligible during intercalation. This behavior results from the blocking up of the framework by Ln3+ ions in LnNb3O9 phases or by the stacking of the three octahedra triangular arrangement in the hexagonal tungsten bronze structure.

Polycrystalline β“alumina isomorphs have been produced by ion exchange of Na β“alumina in various molten salts or salt vapors. The exchanged samples were heated to determine their stable structure after thermal decomposition. The stable structures are classified according to the cation on the conduction plane. Cation size and charge are believed to be the critical factors determining the stable structure.

Auger analysis of sodium β-alumina crystals provides relevant insights concerning Na- transport along the c-axis. In particular, it allows to prove that sodium ion migration is stimulated by electron-irradiation, a result connected to electron-induced relaxation of lattice. Some aspects of the electric fields induced into a dielectric during Auger analysis are discussed.

The synthesis and characterization of H3Oβ”/β-Al2O3 and NH4 + -H3O+β”/β-Al2O3 poly-crystals is described. The role of stress development and control in the intermediate stages of ion-exchange of the NaK-β”/βA12O3 ceramics is analysed and identifies the β-Al2O3 phase as acting as inert reinforcement for the two-phase composite. The Rb + ion-exchange of the intermediate K + β”/β-Al2O3 requisite for NH4+/H3O + ion-exchange to NH4-H3O+β”/βAl2O3 is described as also is the NH4NO3 exchange to the final ceramic. The total weight loss on heating NH4-H3O+β”/βAl2O3 polycrystals to 810°C is 7.4% which agrees with the value expected from the chemical formula. The 25°C conductivity of the grains of NH4 +-H3O + β”/βAl2O3 was 1.7 × 10−4 (ω-cm)−1 and the bulk conductivity was 3 × 10−5(ω-cm)−1.

Na+ beta alumina crystals, ion-exchanged with Eu2+ and Nd3+, were studied using x-ray diffraction and optical spectroscopy. In partially-exchanged crystals, we found different concentrations of sodium and lanthanide ions in the two conduction planes of the unit cell. The results suggest that pairs of sodium ions are rapidly replaced by lanthanide ions in regions of the planes bridged by VAl-Ali-O-Ali-VAl extended defects.