Oxide ion conducting solid electrolyte

X-ray photoelectron spectroscopic (XPS) studies of Ag63,64 and Pt6,56-62 films deposited on YSZ under positive current application conditions have confirmed the proposition2-4 that NEMCA with oxide ion conducting solid electrolytes is due to an electrochemically induced and controlled backspillover of oxide ions on the catalyst surface. 

Gas sensors — (b) Gas sensors with solid electrolytes — Figure 3. Basic principles of gas sensors based on oxide ion-conducting solid electrolytes... 

Shuk, P., Wiemhofer, H.D., Guth, U., Gopel, W., and Greenblatt, M., Oxide ion conducting solid electrolytes based on BijOj, Solid State Ionics, 1996, 89, 179-196. 

The possibility of determining other gas constituents besides oxygen using sensors with oxide-ion-conducting solid electrolytes arises from the thermodynamic equilibria that are set up with oxygen in the gas phase or between particles in the gas phase and the solid electrolyte. 

Figure 25-1. Summary of the calculated electrode potentials of electrodes with oxide-ion-conducting solid electrolytes showing the limits of application of ZtO solid electrolytes and the areas of application of devices and probes with solid electrolyte cells [1, 2].

Signal Functions of Potentiometric Sensors with Oxide-Ion-Conducting Solid Electrolytes... 

For a long time the principle was assumed to be valid that solid electrolytes for gas analysis have to contain such ions as the migrating species which could be formed from particles of the gas phase [6]. According to that, oxide-ion-conducting solid electrolytes are useful for electrode reactions as quoted in Equations (25-8) and (2S-9), and in connection with halogenide ion-conducting solid electrolytes electrode reactions such as... 

If, however, both the O2 concentration and the CO2 concentration vary heavily at the measuring electrode for example, in breathing gas, then one only achieves an applicable analytical signal function with the help of O2 concentration cells. In the case of a measuring electrode, which is connected over a carbonate solid electrolyte oppositely to a C02.02 reference electrode and over an oxide-ion-conducting solid electrolyte oppositely to an O2 reference electrode, one obtains an arrangement which is in principle simple [32, 33] ... 

For the practical application of the oxide ion conducting solid electrolytes for the SOFCs, there is another problem that they usually need high operation temperature over 800°C. In fact, the SOFCs based on the YSZ thin film electrolyte cannot provide acceptable power output due to the fundamental limit of YSZ that it is difficult to obtain enough conductivity below 650°C. The ceria-based oxides are. 

ShukP, Wiemhofer HD, Guth U, Gopel W, Grennblatt M (1996) Oxide ion conducting solid electrolytes based on Bi203. Solid State Ionics 89 179-196... 

Mobius HH (1965) Oxide ion conducting solid electrolyte and their possibilities of application. Basic principles of gas potentiometry (in German). Z physik Chem (Leipzig) 230 396-412... 

Further, the first electrochemical devices based on oxide ion-conducting solid electrolytes, i.e., solid oxide fuel cells, water vapor electrolyzers, and oxygen concentrators, were also developed in the Institute of High-Temperature Electrochemistry. In 1978 the Laboratory of Physical and Chemical Properties of Solid Electrolytes has been renamed to the Solid Electrolytes Laboratory. Different cation-conductive solid electrolytes were investigated in the laboratory. Oxide semiconductor materials with fast ion and electron transport have been studied for different electrode applications in high-temperature electrochemical devices and MHD generators. 

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