Lithium borate glasses B2O3-Li2O-LinX with n=l, X=F, Cl or I are fast ionic conductors. In the perspective of their use as an electrolyte in solid state micro-batteries, spectroscopic investigations of their structure were performed by using experimental techniques sensitive to the local ordering as Raman scattering and F.T.I.R. spectroscopy. In the light of these results, we find that binary and ternary systems (“doped glasses”) with same O/B ratio do not exhibit identical boron-oxygen network. The observed modifications are attributed to interactions between the network and the anions of the doping salt. In addition, the type of the anion plays an important role in the observed effects. We propose here a possible interpretation for the variation of conductivity reported on halide glasses.

Temperature dependent Raman spectroscopic studies of single crystal lithium sulfate are summarized. Coupling between sulfate ion bending modes and the lithium ion translatory modes becomes weaker with increasing temperature until the lithium modes can no longer be observed above 250° C. The temperature interval above 450° in the monoclinic phase is marked by the onset of significant sulfate ion reorientational motion, as evidenced by the bandshape studies of the sulfate ion v1, mode and the librational modes. Bandshape analysis of the v3 mode in the plastic phase strongly suggests that the symmetry of the sulfate ion potential energy environment has planar anisotropy.

The lithium ion-sulfate ion interactions are modeled for correlated sulfate ion configurations as a function of lithium ion position. The results support the role of the octahedral site in lithium ion transitions contributing to the ionic conductivity.

The LaF3-structure has been reinvestigated using diffraction data measured with twinned crystals.

LaF3 is fluoride ion conductor with essentially 3-dimensional conductivity. The conduction perpendicular to the c-axis is shown to occur on paths which include all three sets of fluorine positions in the structure and which connect symmetrically non-equivalent nearest neighbor positions only. This is confirmed by determination of anharmonic temperature factors. The temperature dependence of the harmonic thermal parameters indicates that thermal vibrations are described rather than static disorder. The magnitude of the temperature factors of fluorine is consistent with an intrinsic activation energy of 0.8 eV for fluorine conduction.

A comparative study of the isotypic Na2BeSiO4, Na1.8[Ga0.2Zn0.8]SiO4 and Na1.8[Ga0.2Zn0.8]Ge04 structures has revealed differences in conduction pathway geometries, and calculations show that the two Na-deficient compounds possess larger “bottlenecks”. A conduction mechanism, with Na ions using interstitial sites during migration is suggested.

Neutron diffraction experiments have been performed on AgI and LiCI doped borate glasses. The experiments reveal a substantial progressive increase of the medium range structural ordering when Agl is introduced into the glass, which is manifested in the appearance of an intense diffraction peak at anomalously low Q-values (0=0.8 Å−1). The observation might be attributed either to density deficits within the boron-oxygen network or to the presence of small clusters of AgI. The conduction path model proposed to explain the high ion conductivity may therefore hold for the AgI doped glasses. In contrast, no additional medium range ordering can be observed when LiCI is used as the dopant salt, which casts some doubts on the microdomain model as an explanation of the high ionic conductivity in superionic glasses.

Neutron diffraction data were used to refine the structures of three scandium substituted NASICONS: Na2 ZrSc(PO4)3, R3c Na2.5 Zr1.8 Sc0.2 Si1.7 O12 R3c and Na2.7. Zr1.0 Sc0.2Si1.5 P1.5O12, C2/c. The phosphate (compound 1) exhibited oxygen disorder. The second compound exhibited a similar type of oxygen disorder but also an interstitial Na+ position. The oxygen disorder in compound 2 apparently results from the position of the interstitial Nae whereas it is suggested that the Sc site in Na2 ZrSC(PO4)3 is slightly removed from that of the Zr position, requiring a shift of phosphate groups. In contrast the monoclinic phase does not exhibit oxygen disorder and all the sodium ions reside within the cavities.

The utility of 29Si, 31 p, and 6.7 Li MAS-NMR at 7.05 T to provide structural information in non-oxide chalcogenide glasses is discussed in connection with experimental results obtained on the systems Li2 S-SiS2, Li2 S-SiS2 -P2S5, and Li2 S-P2 S5-B2 S329Si MAS-NMR data indicate that the principles governing glass formation in these systems are fundamentally different from those applicable to stoichiometry-analog oxide glasses. 31p MAS-NMR can be used to identify microphase-separation in glasses containing two network former constituents. The use of the rare isotope 6 Li instead of 7 Li offers the advantage of significantly improved spectroscopic resolution, enabling the presentation of the first comprehensive lithium NMR chemical shift scale in the solid state.

Preliminary results of in-situ NMR studies on lithium intercalated electrode materials in all solid state electro-chemical cells are presented. We discuss the interest for such measurements which, as far as we know, have never been reported before. The design of the cells is briefly presented and our results are compared with previous studies on compounds chemically intercalated with the n-butyllithium technique.

Electric relaxation in CeO2-M203 (M34 sY3+, La3+) solid solutions has been investigated as a function of temperature (373K-673K) using the electric modulus formalism in the frequency range 5 to 107Hz. Two relaxation processes are observed in dilute solid solutions. The low frequency process is identified as a long range migration of free oxygen-vacancies (Process A) and the high frequency process is due to reorientation relaxation of the (MceVo) charged associates (Process B). The relaxation process is analysed using a non-exponential decay function, ø(t)=exp[-(t/τo)B] for O<β≤1, of the electric field. The observed activation enthalpy minimum as a function of dopant concentration for the Process A is explained using the concept of incomplete dissociation of oxygen-vacancies from (MceVo) defect associates and the formation of higher-order defect clusters at higher mole% M203.

A mathematical model has been developed that describes multicomponent transport in solid electrolytes that contain either three or four independent species. The treatment includes homogeneous reactions, short-time transients, and the effects of a co-continuous inert phase. Application of the model to low-frequency AC impedance experiments shows that accurate information on reaction stoichiometries and the nature of the mobile species is needed for proper interpretation of transference numbers and diffusion coefficients. A set of consistency checks for the impedance data is identified that helps distinguish between dilute and concentrated solid ionic conductors and between systems that should be regarded as four-species electrolytes rather than binary electrolytes.

This study reports measurements of electrical properties of the solid state copper ion conductor CuZr2 (PO4)3.

Theoretical techniques are used to examine the energetics of defect formation and ion transport mechanisms in PbFCI. Schottky disorder is found to be the dominant intrinsic defect. The calculated formation energy is in good agreement with experiment. Activation energies for the migration of anion vacancies are presented.

The Nasiconss, Na1+XZr2SiXP3Xo12 O<X<3, includes some of the best solid state sodium conductors known today. Compositions in the interval 1.6<X<2.6 show conductivities comparable to the best aβ-alumina ceramics. It is well known that the ion conductivity of 8-alumina is strongly dependent on the texture of the ceramic. Here a similar behaviour is reported for Nasicon ceramics. Ceramics of the bulk composition Na2.94 Zr1.49Si2. 20P0.80O10.85 were prepared by a gel method. The final ceramics consist of Nasicon crystals with X=2.14 and a glass phase. The grain size and texture of the ceramics were controlled by varying the thermal history of the gel based raw materials and the sintering conditions. The room temperature resistivity of the resulting ceramics varies from 3.65 103 ohm cm to 1.23 10 ohm cm. Using the temperature comparison method and estimates of the area of grain boundaries in the ceramics, the resistivity of the Nasicon phase is estimated to be 225 ohm cm at 25°C. B203 - or Al2O3 -doping of the glass bearing Nasicon ceramic lower the room temperature resistivity by a factor 2 to 5. The dopants do not substitute into the Nasicon phase in substantial amounts.

Measurements of the ultrasonic attenuation and velocity have been made in solid electrolytes with fluorite structure, PbF2, BaF2, and CdF2, from room temperature to temperature at or above the diffuse solid electrolyte transition temperature, Tc. The ultrasonic attenuation peaks observed in this class of materials are associated only with the ionic conductivity saturation rather than in combination with crystallographic phase transition found in many other solid electrolytes. The relaxation rates and Arrhenius activation energies for anion motion above the transition temperature were obtained from the temperature dependence of the ultrasonic attenuation and the theory of local site fluctuations. The ultrasonic attenuation peaks observed for the first time in CdF2was used to define the diffuse transition temperature in this material. An Anomalous peak is also observed in the linear thermal expansion coefficient of PbF2.

Poly(ethylene oxide) is a non-aqueous solvent which can dissolve high concentrations of a wide variety of monovalent and divalent cation salts. The resulting solutions are generally heterogeneous mixtures of crystalline and amorphous regions. The amorphous components have relatively high ionic conductivities, and PEO ‘quasi-solid’ electrolytes and related polymer materials are arguably a new class of electrolyte, with properties in between those of true solids and true liquids. This paper briefly discusses the preparation and properties of PEO electrolytes containing Mg(II), Zn(II), and Pb(II) salts.

Alkali metal polyiodide complexes of polyethers, of the type (polymer)nMIx, [Polymer - poly(ethylene oxide), PEO; poly(propylene oxide), PPO; or poly-(bis(methoxyethoxyethoxy)phosphazene), MEEP, and M - Li or Na] have been prepared and characterized in order to elucidate the nature of the observed ionic and electronic conductivities. Raman spectra of the polyiodide complexes indicate that the relative concentrations of the polyiodide species (such as I3- and higher polyiodides) depend on the salt concentration in the polymer as well as on the iodine to cation ratio. The ionic conduction can best be described by a free volume (VTF) mechanism where both polymer motion and ion mobility are activated processes. The magnitude of the electronic and ionic conductivities are a function of polymer to salt ratio as well as iodine content.

The synthesis of exclusively cation conducting polymer electrolytes based on a nylon-l backbone, ethylene-oxide side chains, and attached dibutyl phenolate anions is described. The tendency for ion pair formation appears to be reduced as the conductivity of the sodium-containing compound reaches −2 × 10−6 S-cm−1 at 50°C. 23Na nuclear magnetic resonance measurements demonstrate: i) motional narrowing of the mobile Na+ resonance above the glass transition temperature; ii) mobile Na+ concentrations of ∼75% at 40°C; iii) insensitivity of the linewidth to applied hydrostatic pressure up to 2 kbar. Similaries between these findings, and those in “conventional” polymer-salt electrolytes are discussed.

Two classes of alkali metal single-ion conducting polymer electrolytes have been characterized and their conductivities examined. Both polymers are sodium ion conductors. The first class is based upon a tetra(alkoxy)-aluminate counterion incorporated into a polyether network, and the second has a sulfonate counterion covalently bonded to a phosphazene backbone. The temperature dependent and concentration dependent conductivities of these polymers are contrasted. Phosphazene polymers that are anion conductors are also discussed.

Raman spectra of a series of PPO-LiClO4 and PPO-NaCF3SO3 complexes have been obtained for different temperatures and salt concentrations to study the various ion associations of the dopant salt. It was found that ion-ion interactions dramatically influenced the internal symmetric stretching modes ν1 of the anions. Splitting of ν1 into a multicomponent band was observed. The intensity profile of the band was found to change rapidly with salt concentration and temperature. A three component band analysis led to the identification of dissociated ions, ion pairs and multiple ion aggregates, respectively. Increased ion association with increased temperature and/or salt concentration was observed for both LiCIO4- and NaCF3SO3- complexes. It is likely to initiate the phase separation and salt precipitation observed in many salt-polymer complexes at higher temperatures. Considerably stronger ion-ion interaction was observed in the NaCF3SO3-system than in the LiCIO4-complex, which may explain the lower conductivities reported for PPO-NaCF3SO3 electrolytes. The drastic conductivity drop observed in both systems at higher salt concentrations can however only partly be due to a decreased concentration of “free” ions, the major effect being attributed to decreased ion mobility.

Ionic migration of cross-linked amorphous Poly (Ethylene Oxide)-LiCF3SO3was investigated by measuring ionic conductivity and diffusion coefficient. Pulsed-Field-Gradient NMR (PFG-NMR) was used for the diffusion measurement. The measurements were carried out at a temperature region between room temperature and 120°C. The PFG-NMR mea-surement shows the two modes of migration of both cation(Li) and anion (CF3 SO3-) for specimens containing plasticizer (CH30(CHeiH20)gH3C). The two modes of migration for anion are present for specimens without the plasticizer. Li+ transport number is found to be less than 0.1 for specimens without the plasticizer. Plasticizer is found to increase the Li+ ion transport number.