Find it at other libraries via WorldCat Limited preview. World Scientific Firm. Bibliography Includes bibliographical references. Contents 1.
sparlersothak.tk Prakash, C. Sanjeeviraja 6. Kingslin Mary Genova Siva Devi Deshpande, N. Satpute Govindaraj Prasada Rao. Singh, O. Pandey Jahja, W. Honggowiranto, E. Kartini Honggowiranto, A. Jahja, E. Reprinted from [ 85 Iwahara H. Proton conducting ceramics and their applications.
Although the conductivity of SrCeO 3 -based ceramics is rather low, their proton transport number is higher than that of BaCeO 3 -based ceramics. The zirconia-based ceramics exhibit lower conductivity than the cerates, but are superior with respect to their chemical stability and mechanical strength.
Dashed line indicates the theoretical line. Various applications can be devised using proton conducting ceramics [ 85,86 Iwahara H.
Solid State Ionic Materials. World Science, Singapore. Chemical Sensors using Proton Conducting Ceramics p Proton conducting ceramics can be used as hydrogen sensors for high-temperature industrial processes. Galvanic-cell-type hydrogen sensors, steam sensors, and hydrocarbon sensors that are usable at high temperature have been fabricated [ 87 Yajima T , Koide K , Fukatsu N , et al.
A new hydrogen sensor for molten aluminum. Sensor and Actuator. These sensors are essentially based on the principle of the hydrogen concentration cell using a proton conducting solid electrolyte. Hydrogen sensors based on CaZr 0.
These sensors could also be applied to other fused metals such as zinc and copper. Iwahara has proposed other applications, such as a hydrogen fuel cell using SrCe 0. When a hydrogen fuel cell is operated inversely, water vapor at the anode is decomposed to form protons that migrate to the cathode, where they discharge to produce hydrogen. This is a type of steam electrolyzer for hydrogen production.
A bench-scale steam electrolyzer was fabricated using a ceramic tube of SrCe 0. Electrical properties of solid oxide electrolytes. Chem Rev. The candidate electrolytes can be divided into two major structures; fluorite and perovskite. Both ceria and high temperature-stabilized zirconia take a fluorite structure, and lanthanum gallates have the perovskite structure.
The fluorite structure is a face-centered cubic arrangement of cations with anions occupying all the tetrahedral sites, which leads to a large number of octahedral voids. This arrangement is rather open and, thus, rapid ion diffusion may be expected. Each additional yttria molecule creates one oxygen vacancy. The conductivity of doped zirconia varies as a function of dopant concentration and has a maximum at or near the minimum quantity of dopant required to fully stabilize the cubic fluorite phase [ 89 van de Graaf MACG , Burggraaf AJ.
Arachi et al. However, this system has been reported to exhibit an aging effect upon annealing at high temperature [ 91 Badwal SPS. J Material Science. Electrical conductivity of stabilized zirconia with ytterbia and scandia. The change in conductivity with the annealing period was found to be dependent on the dopant content. The conductivity of 0. Mizutani et al. Pennington, NJ : The Electrochem. Soc ; This type of scandia-doped zirconia oxide is now widely used as an electrolyte for SOFCs.
However, systematic research on this system was lacking before the study by Kudo and Obayashi [ 94 Kudo T , Obayashi H. Figure 23 shows temperature dependence of the resistivity in the Ce 0. The conductivity of Ce 0. The ceria-based oxide-ion conductors exhibit high conductivity at lower temperatures and have applied as the electrolyte for intermediate temperature SOFCs.
Ceria-based oxide-ion conductors were found to show electron hole conduction under reduced atmosphere [ 88 Etell TH , Flenas SN. Kudo and Obayashi measured the ionic transport number of the ceria-based oxide-ion conductors using an oxygen concentration cell. Figure 24 shows the oxide-ion transport numbers for Ce 0.
The transport number increases with temperature and was less than 0. Arrhenius plot of resistivity for Ce 0. Oxide-ion transport number for Ce 1. In addition to the fluorite structure oxide-ion conductors, some perovskite-type oxides exhibit high ion conductivity. In , Takahashi and Iwahara reported the electrical conductivities of some perovskite-type oxides [ 73 Takahashi T , Iwahara H.
Figure 25 shows the temperature dependence of many perovskite-type oxides. However, the CaTiO 3 -based oxides had low ionic transport numbers at high temperature and in reduced atmosphere. Reprinted from [ 73 Takahashi T , Iwahara H. The electrical conductivities reported by Takahashi and Iwahara for the perovskite-type oxides were lower than those of the fluorite-type oxides. After the pioneering work by Takahashi and Iwahara, some perovskite-type oxides were found to have high oxide-ion conductivity.
Cook et al.
Investigations on BaTh 0. In , Ishihara et al. A superior oxide-ion electrolyte. Eur J Inorg Chem. In particular, Ishihara et al. Figure 26 shows the effect of the addition of alkaline earth cations to the La site in LaGaO 3 on its electrical conductivity. Copyright American Chemical Society.
SOLID STATE IONICS Ionics for Sustainable World Proceedings of the 13th Asian . VARIATION OF IONIC CODUCTIVITY WITH ANNEALING. PDF | The dynamic insight of a lithium phosphate, LiI-LiPO3, glassy electrolyte was studied by using a time-of flight inelastic neutron spectrometer. By utilizing.
The effect of additives at the Ga site of La 0. The results are shown in Figure The highest electrical conductivity was found for La 0. The ionic transport number of La 0. Figure 28 shows the effect of the amount of Mg substitution on the electrical conductivity of La 0. The electrical conductivity increased with the Mg content and a maximum was observed for La 0.
The advantage of the LaGaO 3 -based oxide ion conductors is a high conductivity in the lower temperature range. Ishihara et al. J Alloys Compounds.
Effect of doping of various cations into the Ga sites in LaGaO 3 on the electrical conductivity of La 0. Effect of amount of Mg substitution on the electrical conductivity of La 0. In , a new class of highly oxide-ion conducting solid electrolytes was reported by Nakayama et al.
Chem Lett. Many studies related to their crystal structure and conductivity have been published since the discovery of the lanthanum silicate oxyapatites by Nakayama et al.