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Ionic conductivity
About: Ionic conductivity is a research topic. Over the lifetime, 19412 publications have been published within this topic receiving 519167 citations.
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TL;DR: In this article, an equivalent circuit model of the electrode process was used to fit the impedance data and the time constant for the oxygen surface exchange at the electrodes was derived from the impedance simulation, and the surface chemical exchange coefficients, K chem, were calculated from the time constants as a function of temperature and pO 2.
Abstract: Solid-state electrochemical cells with dense oriented thin film electrodes of La 0.5 Sr 0.5 CoO 3-δ (LSCO) were prepared on (100) surfaces of single-crystal disks of yttria-stabilized zirconia (YSZ) by the pulsed laser deposition technique. Oxygen exchange at the electrodes was studied with alternating current impedance spectroscopy under various temperature and oxygen partial pressure conditions. Three distinctive features were observed in the impedance spectra from high to low frequency corresponding to contributions from the ionic conduction of the YSZ electrolyte, ionic transfer at the LSCO/YSZ interface, and the oxygen exchange on the LSCO electrode surface. An equivalent circuit model of the electrode process is used to fit the impedance data. The time constant for the oxygen surface exchange was derived from the impedance simulation. The surface chemical exchange coefficients, K chem , were calculated from the time constants as a function of temperature and pO 2 . k chem is 7 X 10 -4 cm/s at T = 700°C and pO 2 = I atm. The activation energy at pO 2 = 1 atm is 1.1 eV. The interfacial conductivity data were also derived from the impedance simulations as a function of temperature and pO 2 . The activation energy for the interfacial transport at pO 2 = 1 atm is 1.6 eV.
128 citations
128 citations
TL;DR: Lower critical solution temperatures (LCST)-type of phase diagrams have been encountered for the first time in binary and quasi-binary liquid solutions of ionic liquids and constitute the first experimental support for the existence of a theoretically postulated, but never encountered, special kind of type VII phase diagram.
Abstract: Lower critical solution temperatures (LCST)-type of phase diagrams, including the presence of closed loops, have been encountered for the first time in binary and quasi-binary liquid solutions of ionic liquids. Furthermore, the results constitute the first experimental support for the existence of a theoretically postulated, but never encountered, special kind of type VII phase diagram. Two distinct mechanisms are involved in the appearance of demixing upon temperature increase. These findings underlie the presence of specific, oriented interactions between the ionic liquid, 1-alkyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}amide, [Cnmim][NTf2], and trichloromethane, as well as aggregation phenomena.
127 citations
TL;DR: Fast lithium ion conducting glass-ceramics have been successfully prepared from the pseudobinary system 2[Li1+xTi2SixP3-xO2]-AlPO4 as discussed by the authors.
Abstract: Fast lithium ion conducting glass-ceramics have been successfully prepared from the pseudobinary system 2[Li1+xTi2SixP3-xO2]-AlPO4. The major phase present in the glass-ceramics was LiTi2P3O12 in which Ti4+ ions and P5+ ions were partially replaced by Al3+ ions and Si4+ ions, respectively. Increasing x resulted in a considerable enhancement in conductivity, and in a wide composition range extremely high conductivity over 10-3 S/cm was obtained at room temperature.
127 citations
TL;DR: In this article, the effects of small amounts of Fe doping for Ga site in LaGaO 3 -based oxide on oxide ion conductivity was investigated in a solid oxide fuel cell.
Abstract: Effects of small amounts of Fe doping for Ga site in LaGaO 3 -based oxide on oxide ion conductivity is investigated in this study. It is found that doping a small amount of Fe is effective for improving the oxide ion conductivity in La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3 (LSGM). The highest oxide ion conductivity was exhibited at x = 0.03 in La 0.8 Sr 0.2 Ga 0.8 Mg 0.2-x Fe x O 3 among the Fe-doped samples. Electron spin resonance (ESR) measurements suggest that Fe is trivalent in LaGaO 3 lattice. The application of the Fe-doped LaGaO 3 -based oxide for the electrolyte of solid oxide fuel cell was further investigated. Power density of the solid oxide fuel cell was increased by using Fe-doped LSGM for electrolyte. This can be explained by the decrease in electrical resistance loss by improving the oxide ion conductivity. A maximum power density close to 700 mW/cm 2 was obtained at 1073 K on the cell using 0.5 mm thick La 0.8 Sr 0.2 Ga 0.8 Mg 0-17 Fe 0.03 O 3 (LSGMF) and O 2 as the electrolyte and the oxidant, respectively. Therefore, close to the theoretical open-circuit potential was exhibited by the LSGMF cell. On the other hand, the power density was slightly smaller than that of the cell using Co-doped LSGM as electrolyte, especially, at temperatures lower than 973 K. This may result from the large activation energy for ion conductivity. However, the power density of the LSGMF cell was higher than that of the LSGM cell. Therefore, LSGM doped with a small amount of Fe is a promising electrolyte similar to Co-doped LSGM for the intermediate solid oxide fuel cell.
127 citations