The effect of plasticizer addition on the density, conductivity, glass transition, and free volume behavior of salt containing polyether-urethanes has been examined. The addition of up to 1.5 molal LiC1O4 salt results in an effective crosslinking of the polyether-urethane chains due to the Li+ coordination with the oxygens of the host polymer. This crosslinking decreases inter- and intrachain separation and reduces polymer chain mobility as illustrated by increased density and Tg, decreased free volume, and, at salt concentrations greater than 0.6 molal, decreased conductivity. The addition of approximately 30 wt % tetraglyme plasticizer to the 1 molal LiC1O4/host polymer complex is shown to counter the effective crosslinking resulting in a decreased Tg to a value equal to that of the pure host polymer, increased conductivity, and increased average free volume cavity size to a value equal to that of the pure host polymer. However, the relative number of free volume cavities in the plasticized host polymer/salt complex remains fewer than that of the pure host polymer over the concentration range of plasticizer studied, and in a similar manner the density remains greater than that of the pure host polymer. The room temperature conductivity, free volume, and density behavior in conjunction with the Tg results suggest that the plasticizer addition leads to Li+ coordination with the oxygens of the plasticizer chains as well as increased mobility of the host polymer chains.

Ionic association in lithium trifluoromethanesulfonate (triflate) dissolved in glymes, glycols, model solvents, and high molecular weight poly(ethylene oxide) is studied by analysis of vibrational band structure. Surprisingly, the CF3 symmetric deformation mode is shown to be the most accurate measure of ionic association and the reasons for this are discussed. The nature of various associated lithium triflate species as deduced from ab initio calculations is supported by spectral data presented here. A weak interaction of the triflate anion with certain solvent molecules containing an alcohol OH group is observed. Finally the temperature dependence of ionic association in a complex of lithium triflate and high molecular weight poly(ethylene oxide) is described.

Conductivity has been measured for mixed alkali systems of LixNa1-xClO4 (PEO)n with n = 6, 16 and 40, and a mixed anion system of LiClxI1−x(PEO)16 complexes with varying concentrations of x. In the LixNa1−xClO4 (PEO)n complexes, it shows no unusual conductivity behavior. In the LiClxI1−x(PEO)16 complexes, the conductivity shows positive deviation from additivity in the mixed-anion region and the mixed-anion effect is also observed in the semicrystalline-toamorphous transition temperature.

The equilibrium sorption, inverse gas chromatography (dynamic sorption), optic microscopy, X-ray diffraction and visible light scattering methods were used to investigate the structure of poly(ethylene oxide) (PEO) blended with poly(vinylacetate) and poly(siloxanes) as matrices of polymer solid electrolytes. It was shown that the melting point (Tm) and the degree of crystallinity in such PEO-blends were lower than in pure PEO. The Gibbs energy of mixing and the compatibility parameter (X12) were obtained for PEO-blends. In the vicinity of Tm all the systems were thermodynamically compatible, however at the ambient temperature they were microgeterogenous and compatible only in the narrow range of PEO-modificator contents. This must be taken into consideration while creating solid polymer electrolytes based on polymer blend matrices.

Because of the procedures associated with the deconvolution of the data present in an EXAFS spectrum, the experimental XAFS spectra also include both the edge and XANES regions. It is possible to obtain additional structural and chemical information from the data associated with these regions of the XAFS spectrum and in this work we have re-examined the XAFS spectra for a series of polymer electrolytes. These spectra were originally recorded for EXAFS analysis. The XANES spectra for PEOn:CaBr2 electrolytes confirm that the behaviour of calcium polymer electrolytes appears to be very different from that of other divalent based electrolytes. We have also examined the edge features for PEO8:NiBr2 samples which were subject to different thermal histories and evidence for phase separation is presented.

X-ray absorption spectroscopy (XAS) has been very useful in elucidation the structure of polymer electrolytes, in particular ion-ion and ion-polymer interactions. Several examples are discussed. One is the use of XAS to study the effect of temperature on ion pairing. The other is the elucidation of the mixed cation effect on electrolyte conductivity. Several investigations have indicated abnormally high oxygen coordination numbers for cations. These are discussed.

Polyaniline has been synthesized in propylene carbonate by galvanostatic electrochemical polymerization at current densities between 16 and 1000 μA/cm2. Earlier results for polypyrrole have shown that low and high current density films have different properties: The films synthesized at low current density have a higher conjugation length and a more regular structure. The corresponding effect in PANI has been investigated by cyclic voltammetry and UV/visible spectroscopy. Simultaneous measurement of cyclic voltammograms and the absorbtion of selected spectral lines is used because of the complex nature of the PANI system which involves several redox systems as well as forms differing in the degree of protonation and morphology.

The main result is that the method of galvanostatic synthesis at low current densities (-16 μA/cm2) produces polyaniline polymers of different, more conjugated and more regular structure than those prepared at higher current densities. The standard method of in situ layer-by-layer polymerization of conducting polymers during cyclic voltammetry often results in uncontrolled and unmeasured current densities of 0.5-2 mA/cm2 which produces a film that probably has a less regular structure containing more deviations from ideality.

Layer-by-layer molecular self-assembly has been used to fabricate multilayer heterostructures containing poly(phenylene vinylene) (PPV) and a variety of polyanions. These ultrathin films exhibit widely different photoluminescence intensities and peak positions (emission color) depending on the polyanion used. The characteristics of light-emitting devices based on such films are described. This represents the first demonstration of working organic light-emitting diodes, the active layer of which consists of ultrathin, self-assembled films of between 130 - 500 Å

Electrosynthesized polyaniline (PANi) can be chemically functionalized by incorporation of palladium clusters. The functionalization of electrochemically, freshly prepared and dried PANi film occurs spontaneously during the relaxation process. This process is carried out in sulfuric acid containning palladium salt. The material properties of the new composite PANi-Pd film were investigated by applying electrochemical, UV-visible spectroscopic and surface microscopy techniques. The PANi-Pd composite materials behaved electrochemically different than PANi film alone or Pd film deposited electrochemically. This finding is particularly important for developing layers for chemical sensors, electrocatalysis or supercapacitors applications.

Molecular layer-by-layer build-up on a variety of substrates is demonstrated for doped polyaniline (PAn) alternating with non-ionic water soluble polymers. The adsorption is enabled by the strong interchain interactions with PAn, such as hydrogen bonding. Multilayer build-up has been demonstrated with four distinctly different non-ionic water soluble polymers: poly(vinyl pyrrolidone) (PVP), poly(vinyl alcohol) (PVA), poly(acrylamide) (PAAm), and poly(ethylene oxide) (PEO). Thus, non-ionic water soluble polymers containing a wide variety of functional groups such as amide, hydroxyl or ether groups can be used to successfully fabricate multilayer thin films with polyaniline. FTIR spectroscopy measurements show the PAn to be hydrogen bonded in these multilayer films. Conductivities for multilayer films are on the order of 1-4 S/cm for films doped with methane sulfonic acid. Conductivities on the order of 0.1 S/cm can be achieved for a single mixed layer self-assembled from a mixed solution of PAn/PVP or PAn/PAAm.

In 1992, Bellcore researchers demonstrated the feasibility of a liquidelectrolyte Li-ion system based on the Li1 + xMn2O4/C redox couple which presents cost and environmental advantages over the LiCoO2/C system. However, neither of these systems are free of the risk of electrolyte leakage. To address this problem, we investigated various means of trapping the liquid electrolyte in a polymer matrix and developed the first practical plastic Li-ion battery. In this paper we compare the performance and scaleability of this technology to those of its liquid Li-ion counterpart. Based on the “hybrid polymer” concept, this battery exhibits excellent cycle life (more than 2500 cycles) and good rate capabilities (the battery can deliver 95% of its total capacity at a 1C discharge rate). This technology is compatible with various positive (LiMn2O4, LiCoO2 and LiNiO2) and negative (carbon, graphite) electrode materials.

Supercapacitors are now attracting much attention as an electric vehicle power source. The present study focuses on redox supercapacitors with electronically conducting polymers as electrode materials. Performance data of a symmetric supercapacitor based on p-doped poly(pyrrole), of an unsymmetric supercapacitor based on p-doped poly(pyrrole) and poly(3-methylthiophene), and of a symmetric sypercapacitor based on p- and n-doped poly(dithieno[3,4-b:3',4'-d]thiophene) are here compared.

The theoretical background for potentiometric and conductometric (bulk and surface) sensors is briefly discussed with regard to the usual application, viz. the detection of redox-active gases, and the importance of understanding chemical diffusion is stressed in this context. It is then shown how the analogous concept applied to acid-base interactions leads to powerful possibilities to measure partial pressures of acid-base active gases such as CO2, NH3 and H2O. Two examples of novel sensor principles are discussed: i) The response of the surface ionic conductivity of AgCl or CaF2 upon changes of partial pressures of (Lewis) basic or acid gases can be used to sense NH3 and BF3. ii) In the major part of the paper it is shown how the deliberate use of overall acid-base cell reactions in potentiometric arrangements leads to a fast and precise CO2-sensor. For this purpose, open reference electrodes based on Na2Ti6O13 or Na2SnO3 have been constructed. Owing to the criteria developed in the text the whole cell can be exposed to a CO2 and O2 containing atmosphere without the necessity of sealing. Detailed results are given.

The growth of high-quality, pin-hole free, ytrrium doped ZrO2 thin films is of great interest for a variety of electrochemical applications such as fuel cells and oxygen gas separation devices. In the work, we have grown polycrystalline thin films of ytrrium doped ZrO2 on thick porous Al2O3 substrates in multilayer La1-xSrxMEO3/YSZ/La1-xSrxMEO3 (ME = Mn, Co) configurations using a combination of single-target RF magnetron sputtering and electron beam physical vapor deposition techniques. The structure and morphology of these films have been studied using X-ray diffraction, and Scanning Electron Microscopy techniques. The ionic conductivity of the thin films has been measured using AC impedance analysis.

An electric field sensitive moving hot spot appeared when a dc voltage over 5 V was applied at room temperature to GdBa2Cu3O7-δceramic thin rods under oxygen partial pressures ranging from 0.05 to 1.00 atm (5 kPa to 100 kPa). The spot moved to the negative electrode, and the direction of movement could be reversed time after time by switching the positive and negative electrode. This is believed to be caused by electric field movement of oxygen ions, thereby generating an ionic current. The total current after the appearance of the hot spot was independent of the applied voltage for every oxygen partial pressure, PO2. However the current and spot velocity increased significantly with increasing PO2. By the best of the authors's knowledge this is the first report on the influence of the PO2 on the moving hot spot. The potential use of this phenomenon as an oxygen sensor will be shown.

Thin films of V2O5 were prepared using the flash-evaporation technique. Amorphous and polycrystalline samples were characterized by X-ray diffraction, Raman spectroscopy and XPS analysis. The electrical properties of the samples were determined. The effect of either deposition parameters or post-deposition treatments, i.e., annealing in various atmospheres and at different temperatures, on transport properties are presented.

Electrochemical characteristics are evaluated in V2O5/LiCIO4-PC/Li microbatteries. The discharge curves present several voltage plateaus, similar to those already observed in cells with bulk V2O5 cathodes. Kinetics of lithium intercalation have been investigated as a function of the growth conditions of V2O5 films. Chemical diffusion coefficient and enhancement factor are calculated as a function of the degree of lithium intercalation. All the results are compared with previous reported results for bulk vanadium oxides. The relationship between the crystallinity of the films and their electrochemical features is also discussed.

Electrochemical characteristics of Li/V6O13 microbatteries are evaluated in relation with the crystallinity and morphology of thin-film cathodes. Thin films of V6O13 were prepared using the flash evaporation technique. Amorphous and polycrystalline samples were characterized by X-Ray diffraction, Raman spectroscopy and conductivity measurements. The effect of either deposition parameters or post-deposition treatment are presented in this work. Thermodynamics and kinetics of lithium insertion were studied in V6O13 thin films obtained with various growth conditions. Discharge curves present different types of behavior depending on the cathode morphology. Diffusion coefficients and enhancement factors were calculated as a function of the degree of lithium intercalation.

A photochromic effect is observed in WO3-based electrochromic devices with an ion-conducting polymer as electrolyte. Upon exposure to sun light, the electrochromic cells become blue. This is due to a change of color of the WO3 electrode. The photoeffect on this layer is due to a simultaneous insertion reaction (reduction) of the WO3 material and a photooxidation of water contained in the polymer. It is reversible and therefore not destructive for the complete device. The study of the transmittance and rest potential as a function of the time of exposure to light shows that a steady state is reached in c.a. 10 hours. The addition of U.V.-cut filters changes the reached steady-state, indicating that the photochromic effect is dependent upon the structure of the WO3 material.

Nickel oxide electrochromic thin films were prepared by reactive DC magnetron sputtering. As-deposited optical property and electrochromic behavior strongly depended on the target operation mode and the substrate temperature. In the condition of low oxygen flow ratio (∼1%), the deposition rate can be raised up to 40 nm/min at the power of 60 W. The sample with the deposition rate of 30 nm/min exhibited the best electrochromic performance when the substrate temperature was kept to 200°C-300°C during sputtering. The integrated luminous transmittance of the best sample could be controlled from 6.6% to 82.3%.

In recent years there has been an enormous increase in the application of thin film technologies in the fabrication of solid state electrochemical devices. Devices in which thin film components are utilized are, e.g. solid oxide fuel cells (SOFCs), thin film rechargeable batteries, and chemical gas sensors. Chemical vapour deposition (CVD) is one of the synthesis techniques for the fabrication of thin film components for solid state electrochemical devices. This paper will focus on the application of novel CVD techniques for the fabrication of the thin film components of one of these devices, i.e. the solid oxide fuel cell. A new SOFC design concept which uses only one gas phase synthesis method will be presented.