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High Ionic Conductivity (high + ionic_conductivity)
Selected AbstractsLow-Temperature Superionic Conductivity in Strained Yttria-Stabilized ZirconiaADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Michael Sillassen Abstract Very high lateral ionic conductivities in epitaxial cubic yttria-stabilized zirconia (YSZ) synthesized on single-crystal SrTiO3 and MgO substrates by reactive direct current magnetron sputtering are reported. Superionic conductivities (i.e., ionic conductivities of the order ,1 ,,1cm,1) are observed at 500,°C for 58-nm-thick films on MgO. The results indicate a superposition of two parallel contributions , one due to bulk conductivity and one attributable to conduction along the film,substrate interface. Interfacial effects dominate the conductivity at low temperatures (<350,°C), showing more than three orders of magnitude enhancement compared to bulk YSZ. At higher temperatures, a more bulk-like conductivity is observed. The films have a negligible grain-boundary network, thus ruling out grain boundaries as a pathway for ionic conduction. The observed enhancement in lateral ionic conductivity is caused by a combination of misfit dislocation density and elastic strain in the interface. These very high ionic conductivities in the temperature range 150,500,°C are of great fundamental importance but may also be technologically relevant for low-temperature applications. [source] Nanoscale Organic Hybrid ElectrolytesADVANCED MATERIALS, Issue 33 2010Jennifer L. Nugent Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature ; yet manifest high ionic conductivity and good electrochemical stability above 5V. [source] Solid Composite Polymer Electrolytes with High Cation Transference NumberISRAEL JOURNAL OF CHEMISTRY, Issue 3-4 2008Hadar Mazor This work presents the electrochemical and structural study of the dual modified composite LiBOB-based polymer electrolyte. Modification has been carried out by calix[6]pyrrole (CP) anion trap and nanosize silica filler. The main advantage of the use of LiBOB salt is the high ionic conductivity at near-ambient temperatures and low solid-electrolyte interphase (SEI) resistance. The conductivity of LiBOB:PEO20:CP0.125 with SiO2 is slightly lower than 10,5 Scm,1 at 30 °C, a value higher by about two orders of magnitude than that of the semi-crystalline LiCF3SO3 (LiTf)-PEO system. At 75 to 90 °C the bulk ionic conductivity of modified LiBOB polymer electrolyte approaches 1 mScm,1. The transference number of dual-modified LiBOB-polymer electrolyte is about 0.8 at 75 °C. Cyclic voltammetry tests showed a wide electrochemical stability window of the composite polymer electrolyte. The peak power of Li/MoOxSy cell with the polymer electrolyte film containing CP and SiO2 reaches 2.2 mW/cm2 and 3.0 mW/cm2 at 90 and 110 °C, respectively. [source] Supercapacitor studies of electrochemically deposited PEDOT on stainless steel substrateJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2007S. Patra Abstract There has been increasing interest on various properties and applications of electronically conducting polymers. Polyethylenedioxythiophene (PEDOT) is an interesting polymer of this type as it exhibits very high ionic conductivity. In the present study, PEDOT has been electrochemically deposited on stainless steel (SS) substrate for supercapacitor studies. PEDOT/SS electrodes prepared in 0.1M H2SO4 in presence of a surfactant, sodium dodecylsulphate (SDS), have been found to yield higher specific capacitance (SC) than the electrodes prepared from neutral aqueous electrolyte. The effects of concentration of H2SO4, concentration of SDS, potential of deposition, and nature of supporting electrolytes used for capacitor studies on SC of the PEDOT/SS electrodes have been studied. SC values as high as 250 F/g in 1M oxalic acid have been obtained during the initial stages of cycling. However, there is a rapid decrease in SC on repeated charge-discharge cycling. Spectroscopic data reflect structural changes in PEDOT on extended cycling. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Structure and oxygen mobility in mayenite (Ca12Al14O33): a high-temperature neutron powder diffraction studyACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2007H. Boysen The structure of mayenite, Ca12Al14O33, was investigated by neutron powder diffraction up to 1323,K. It has been described previously as a calcium,aluminate framework, in which 32 of the 33 oxygen anions are tightly bound, containing large cages, 1/6 of them being filled randomly by the remaining `free' oxygen. At ambient temperature excess oxygen was found, corresponding to the composition Ca12Al14O33.5 which was attributed to the presence of hydroxide, peroxide and superoxide radicals in the cages. Above 973,K these are lost under vacuum conditions and the composition becomes stoichiometric. From the refined structural parameters it is concluded that the structure is more adequately described as a relatively stable aluminate framework consisting of eightfold rings of AlO4 tetrahedra with disordered Ca and `free' O distributed within. At high temperatures the density of the `free' oxygen is extremely spread out, with the expansion being related to the high ionic conductivity of this material. Since no continuous density distribution between adjacent cages was found and the `free' O forms bonds with part of the Ca, the diffusion proceeds via a jump-like process involving exchange of the `free' oxygen with framework oxygen. The results confirm the recent theoretical predictions of Sushko et al. [(2006), Phys. Rev. B, 73, 014101-1-10]. [source] Hexacopper(I) phosphorus(V) bromide penta(selenide/sulfide), Cu6P(Se0.7S0.3)5BrACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2008A. Gagor This work illustrates possible diffusion paths for CuI ions in a highly disordered structure of a superionic conductor of the argyrodite family. The Cu6P(Se0.7S0.3)5Br cubic structure is built from a [P(Se0.7S0.3)5Br] framework in which CuI ions are distributed in various tetrahedral, triangular and linear sites. There are two types of disorder in the structure. The first type results from the fact that there are fewer CuI ions than the number of positions available for them in the unit cell. The second type is due to the static distribution of Se and S atoms in the [P(Se0.7S0.3)5Br] framework. The title compound is a solid solution of two efficient ionic conductors, namely Cu6PSe5Br and Cu6PS5Br, in which high ionic conductivity results from order,disorder phenomena in the copper substructure. To shed light on the distribution of CuI ions in disordered Cu6P(Se0.7S0.3)5Br, we refined their positions using a combination of a nonharmonic approach and a split-atom model. At room temperature, CuI ions show strong anharmonic vibrations along the edge of the (Br)4 tetrahedra. The probability density functions of the CuI ions overlap and reveal possible diffusion paths. [source] | |||||||||||||