The conductivity of the Li2O:P2O5:MO3 (M = Cr2, Mo, W) glasses increases as P2O5 is progressively substituted by MO3 and as the Li2O content increases. Amongst the glass compositions studied, the 0.50Li2O:0.20P2O5:0.30WO3 glass has the highest conductivity at 25°C of 2. 1×10−6 ×−1 cm−1. The glass transition temperature of the glasses increases initially with network former substitution, reaches a maximum at around MO3/P2O5 = 1, and decreases with further substitution. X-ray photoelectron spectroscopy reveals the presence of M ions in more than one oxidation state and oxygen species such as P=O, P-O-P, P-O, M-O-M, M-O and P-O-M. Raman spectroscopy shows that the Li2O:P2O5:MoO3 and Li2O:P2O5:WO3 glasses consist of PO4, MoO4 (WO4) and MoO6 (WO6) polyhedra while the Li2O:P2O5:Cr2O3 glasses consist of the PO4 and CrO6 polyhedra only. The phosphate groups are preferentially modified by Li2O in comparison with the tungstate, molybdate and chromate groups. The increasing number of non-bridging oxygen atoms per phosphate group may be related to the increasing conductivity with the progressive substitution of MO3 for P2O5.

The quality of the metal/ceramic interface of solid ionically conducting materials is an important when undertaking impedance spectroscopy measurements. One major concern is the contact area between the metal and the ceramic. This work focussed on the treatment of the ceramic to the metal application by utilizing a standard quality Na-β" alumina. Next, a number of different metals were applied to the ceramic surface by different techniques, i.e. sputtering and evaporation, to serve as blocking electrodes in impedance spectroscopy measurements. The impedance spectroscopy measurements were carried out at temperatures from 30 - 300°C over a frequency range from 1 to 5 ×105 Hertz. The results are discussed in terms of the various parameters of impedance plots. Surface analysis techniques were applied to investigate the metal/ceramic interface before and after impedance spectroscopy measurements.

Structural refinements have been carried out on the Y2(ZryTi1−y)2O7 system for increasing amounts of Zr substitution. The structure changes from an ordered pyrochlore structure (superstructure of the fluorite structure) to an anion-deficient fluorite structure. Separate processes govern the disordering of the cation and anion arrays. In particular, the anions begin to disorder at lower values of y than the cations. For intermediate compositions, a minor amount of fluorite phase coexists with the primary partially-disordered pyrochlore phase.

Protonic conduction of SrZrO3 doped with Y3+(5%), yb3+(5 and 10%) and Sc3+(5, 10, 15 and 20%) has been investigated in a frozen-in condition at 20-400°C following a high-temperature pre-treatment in water vapor. Water uptake was also determined gravimetrically. The pure sample shows no proton incorporation and relatively low conductivity. The oxygen partial pressure dependence of conductivity under dry atmosphere shows hole conduction only when P(O2) >10−5 atm. All of the doped samples show good protonic conduction and a non-classical H2O/D2O isotope effect. The conductivity and water uptake is always higher for samples slowly cooled from the pre-treatment than for quenched samples. The activation energy, as well as the pre-exponentials, of the slowly cooled samples consistently suggest Stage II behavior, with an activation energy for proton migration of 0.61±0.02eV and an effective proton concentration close to the actual concentration. It is concluded that SrZrO3 deserves serious consideration as a proton electrolyte.

The surface oxygen exchange on oxides with high oxygen ion mobility is modelled with a two step reaction with adsorbed mono-atomic oxygen species as intermediate. Interpretation of the Po2 dependence of the exchange rates, following from this model, indicates that these adsorbed oxygen atoms are singly charged.

For the stabilized δ-Bi2O3 solid electrolyte a good agreement has been found between the isotope exchange model and the electrochemical study of the oxygen exchange using gold electrodes. For the mixed La-Sr cobaltite perovskite a change in the surface exchange reaction is observed going from room temperature to 600°C. Indications are that above 450°C the bulk exchange is rate limiting with a (Po2)−1 dependence while below this temperature it is assumed that the dissociative adsorption is rate limiting with a (Po2)1/2 dependence.

The electrochemical behaviour of a polymeric supported uranyl phophonate film, when it is placed in contact with solutions of two generating electrolytes, (H2PO3C6H5 and UO2(NO3)2) at different concentrations, is studied by AC impedance spectroscopy and diffusion potential measurements. The equivalent circuit associated to the film and some of its characteristic electrical parameters (Rf and Qf) are determined. The cation transport numbers in the film (t+ = I+/I) with both electrolytes as well as their variation with concentration are also obtained. Differences found in the Qf parameter for both film/electrolyte systems are attributed to the different values of the transport numbers.

The crystal structure of β-Pb0.9Bi0.1F2.1 has been investigated in the temperature range 294 to 710K by single crystal X-ray diffraction method. Phase transition is observed at about 700K and the mean square displacements (MSD) of metal and fluorine ions show a rapid increase near the transition temperature. The fluorine ions do not show anharmonic thermal vibrations in the regular site in the temperature range.

Fast-ion conduction in solids is considered a paradigm for structure-property relation where ionic conductivity σ = nqµ, n the concentration of charge carrier q, and µ. the mobility of the carrier. The critical conductivity determining factor, ceteris paribus, is the carrier mobility which depends on the geometry of anion array and structure in the solid. Factors inherent in the structural framework include “free” volume, “bottleneck” size, lattice disorder, etc. Other non-structural factors that can play a vital role, even a dominant role, in enhancing ionic conductivity are charge carrier concentration, ion-ion interactions or bonding characteristics, vibrational amplitudes of neighboring ions, lattice compressibility or resiliency, rotational motion of anions, ion size, etc. Many aspects of these factors will be examined in the light of recent studies and the results on some isostructural and isomorphous sulfates and other related structures to evaluate their relative contributions.

The electrochromic behavior of crystalline WO3 thin films of two different crystal structures was investigated. The films were deposited on ITO-coated Coming 7059 glass and transparent single crystal sapphire substrates by electron beam evaporation. The usual monoclinic crystal structure was obtained by post-annealing films deposited at low substrate temperatures. An alternative phase was generated by in-situ growth of crystalline films at high substrate temperatures. The reversible electrochemical insertion of Li was demonstrated by cyclic voltammetry. Optical switching was observed by comparing visible transmittance, visible reflectance, and infrared reflectance spectra of films before and after Li intercalation. The two film types assumed similar crystal structures upon lithiation. High infrared reflectance in the monoclinic phase was described well by an elementary freeelectron plasma edge model. However, the high-Ts. film exhibited significantly poorer reflectance in the infrared when lithiated.

Thin films of tin-doped indium oxide (I.T.O.) were produced by r.f. sputtering and lithiated electrochemically in LiClO4-PC. X-ray diffraction studies showed a cubic structure with a small increase in the cubic lattice parameter with x up to unity (LixITO). Electrochemical studies indicated that Li insertion is reversible, at least over a small number of cycles. Spectral transmittance decreased slightly with considerable levels of insertion indicating low electrochromic colouration efficiencies and making thin film I.T.O. a suitable counter-electrode material for electrochromic window systems.

Electrochemical studies performed by linear potential scan voltamperometry on the monosubstituted intermetallic hydrides LaNi4.5M0.5, with M=AI, Mn or Co, confirm previous observations [ 14, 16, 20] of the influence of the nickel substitute on the rate of hydrogen insertion/desinsertion in solid gaz : the rate of discharge is faster for the Co and Mn substituted hydrides than for the Al one : during a controled discharge process by potential step of 20mV during 10 hours, hydrogen full capacity is desinserted over a potential range of 200mV in 80 hours for LaNi4.5AI0.5, over 130mV in 40 hours for LaNi4.5Mn0.5 and over 50mV in 30 hours for LaNi4.5Co0.5

Coupled techniques of real time neutron diffraction and linear potential scan voltammetry applied to the in situ study of the charge/discharge of a LaNi4.5A10.5Dx electrode in a KOD 7N electrolyte gives account for the respective variation of the cell parameters of the α and β phases[ 11] and provides access to the hydogen desinsertion kinetics from both phases. The decrease rate of the unit cell volume of the α phase is found to be 4.8 10−3 A3/hour whereas that of the β phase is 61 10−3 A3/hour. At the end of the discharge process occurence of isolated 13ph ase domains is attributed to the faster rate of hydrogen desinsertion in the β phase than in the (β phase, which is in all likelihood at the origin of the loss of capacity observed during cycling for this electrode.

Layered compounds are known to form lithium intercalation complexes as electron donor systems. A charge transfer which can strongly affect the electronic properties of the host lattice, and a change of preferential crystallographic parameters without destruction of the original structure are the main effects occuring during intercalation. Optical spectroscopies such as Raman scattering, far-infrared reflectivity, absorption measurements and photoluminescence have been carried out for the study of electronic and structural modifications. Upon lithium intercalation, lattice dynamics and electronic band structure change in numerous layered compounds. The optical properties of transition-metal dichalcogenides, non-transition metal chalcogenides and transition-metal oxides are presented and discussed with the aim of a better understanding of the intercalation process and establish some guide lines for improving the performances of these materials in their most important applications.

Impedance spectroscopy methods were used to characterize the electrical properties of the solid solution formed in the system LiTaO3 -“Li2Mn4O9”.

Involved parameters were calculated using equialent circuits. Activation energy values were decreasing from around 1.3 eV for lowest concentration of Mn4+ until around 0.8 eV for higher Mn4+ contents. Results will be discused in terms of Z' vs Z" and Arrhenius plots. The ferroelectric character was stablished using the real part of the permittivity against temperature. Curie temperature values Tc were found decreasing toward higher concentration of Mn4+ in the range 630-580°C.

Time resolved impulsive stimulated Raman scattering (ISRS) is used to characterize the lowest frequency A1 phonon-polariton mode in lithium tantalate. The anomalously high and wavevector-dependent damping rates observed are explained in terms of coupling of the polariton to a weakly Raman-active relaxational mode and to two heavily damped vibrational modes. The dynamics of the relaxational mode are explored further through temperature dependent ISRS studies. Femtosecond optical pulse shaping is used for multiple pulse ISRS at temperatures lower than 120K where single pulse excitation led to photorefractive damage.

Nuclear and electronic responses in highly nonlinear optical glasses are investigated using femtosecond polarization discrimination four wave mixing experiments.

FTIR results from cuprous oxide (Cu2O) and cupric oxide (CuO) films prepared by MOCVDtechnique were presented. According to FTIR and XRD results, Cu2O films can be prepared by MOCVD using 0.20 tort of copper acetylacetonate (Cu(acac)2) vapor and 150 torn of oxygen, at a deposition temperature of 340°C. The strong reductive tendency of Cu(acac)2 vapor in the MOCVD process is noted, as the oxidation state of copper was reduced from 2+ in Cu(acac)2 to 1+ in the Cu2O film. Cu2O films have a strong IR absorption band at 610 cm−1. CuO films were prepared at 0.20 tort of Cu(acac)2 vapor and 190 torr of oxygen, at a deposition temperature of 420°C. The IR bands of CuO films located at 440 cm−1, 480cm−1, and 540cm−1. The XRD results indicated that Cu2O films have a preferential orientation at (111) plane. From IR study, it appears that the MOCVD processing condition has an impact on the film microstructure, which in term influenced the band position and band shape of corresponding IR bands.

X-ray photoelectron spectroscopy measurements and synchrotron radiation reflectivity and measurements in the photon energy range between 5eV and 30 eV are reported for yttrium stabilised zirconia single crystals. From the present data some behaviour of the valence band and conduction band electronic structure are elucidated. Two features present in the valence band XPS spectra, not explained on the basis of one-clectron theory, are tentatively assigned to simultaneous two electron excitation.

Systematic X-ray diffraction studies of thermal expansion in CsHSO4, CsDSO4, RbHSO4 and Rb3H(SeO4)2 crystals have been carried out. An analysis of the results showed that the fast protonic conductivity is closely connected with the characteristic features of the structure, symmetry and orientation of hydrogens bonds in the crystals of MeXAO4 (Me=NI4, Rb, Cs; X= D,H; A= S,Se) family.

Rechargeable, polymer lithium batteries are today considered as very promising advanced power sources for electric vehicle and/or consumer electronics. Many polymer electrolytes, some of which having very high ambient temperature conductivity, have been developed and characterized. However, very little attention has been so far dedicated to the study of the characteristics of the lithium electrode interface. Since the clarification of the interfacial phenomena is crucial in assessing the effective impact of polymer batteries, we have undertaken a detailed investigation of the Li passivation processes in most relevant electrolyte media and in this work we report results obtained in highly conductive cells using electrolytes formed by the immobilization of lithium solvates in polymer networks.