Ionic conductivity of stabilized

It has been reported (4,5) that solid electrolyte sensors using stabilized zirconia can detect reducible gases in ambient atmosphere by making use of an anomalous EMF which is unusually larger than is expected from the Nernst equation. However, these sensors should be operated in a temperature range above ca. 300°C mainly because the ionic conductivity of stabilized zirconia is too small at lower temperatures. On the other hand, solid state proton conductors such as antimonic acid (6,1), zirconium phosphate (8), and dodecamolybdo-phosphoric acid (9) are known to exhibit relatively high protonic conductivities at room temperature. We recently found that the electrochemical cell using these proton conductors could detect... 

Stabilized zirconia — Figure. Oxygen ionic conductivity of stabilized zirconia ceramics as a function of reciprocal temperature at different dopant concentrations. See [ii] for details... 

A number of studies have also shown that the ionic conductivity of stabilized zirconia depends on the size of acceptors the conductivity tends to be highest with a minimization of the conductivity activation energy for those acceptors whose ionic radius closely matches that of host cation... 

This observation suggests that the ionic transport can be related to the defect energy, which is defined by the interaction between the acceptors and oxygen sublattice. This interaction results in the barrier for ion hopping between equivalent positions in the lattice. Therefore, there has been considerable effort to optimize the ionic conductivity of stabilized zirconia by controlling the acceptors concentration and their size [1, 3]. 

Yamahara K, ShoUdapper T Z, Jacobson C P, Visco S J, de Jonghe L C (2005) Ionic conductivity of stabilized zirconia networks in composite SOFC electrodes. Sol Stat Ionic 176 1359-1364... 

The maximum ionic conductivities of the complexes XV/LiAsF and XV/ LiCl04 at the same temperature are 5x10 and 6x10 S cm respectively [10]. XV is completely amorphous from -100 to +100 °C. Its Tg is -74 °C in the absence of salt. Its dimensional stability is considerably higher than that of the linear MEEP with a similar molecular weight, and it forms free-standing films. 

SOE cells utilize solid ceramic electrolytes (e.g. yttria stabilized zirconia) that are good oxygen ion (0 ) conductors at very high temperatures in the range of 1000°C [8]. The operating temperature is decided by the ionic conductivity of the electrolyte. The feed gas, steam mixed with hydrogen, is passed through the cathode compartment. At the cathode side, the reaction is... 

Figure 10. Ionic conductivity of jully and partially stabilized zirconia bodies...

As can be seen, the mechanical strength of the partially stabilized body is approximately twice that of the fully stabilized and the thermal expansion is approximately 30% lower. Because of this, the thermal shock resistance of the PSZ body is greatly improved. The ionic conductivity of the PSZ body is lower but is still adequate for automotive applications. Figure 10 compares the conductivity of a yttria partially stabilized zirconia body with several fully stabilized bodies. 

Significant differences between molecular solvents and ILs are based on the component species. This is not as a serious problem for the electrochemical devices that require non-specific ions. The unique properties of ILs, especially their high ionic conductivity, thermal stability and non-volatility are great advantages for electrolyte solutions in electrochemical devices... 

Pang G., Feng S., Tang Y., Tan C. and Xu R., Hydrothermal synthesis, characterization, and ionic conductivity of vanadium-stabilized Bii7V3033 with fluorite-related superlattice structure, Chem. Mater 10 (1998) pp. 2446-2449. 

The phase diagrams and ionic conductivities of anion-deficient ZrO2 compounds have been widely investigated, to probe the influence of both dopant size and concentration (e.g.. Ref. [95]). Whilst Sc" + doped systems possess the highest values of ionic conductivity, factors such as cost and long-term stability have favored the use of (Zri j,Yj,)O2 x/2 as the current "best material, in which the m t and t c transitions are observed at x 0.05 and xw0.16, respectively [96]. On increasing dopant (anion vacancy) concentration, the ionic conductivity initially increases with X, but reaches a maximum close to the lower limit of stability of the c phase and then decreases rapidly [97]. Many theoretical studies have attempted to provide an explanation for this effect, and it is generally accepted that vacancies are trapped... 

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