Solid Oxygen-Conduction Electrolyte

Key words Solid Oxygen-Conduction Electrolyte/Doped Cerium Oxide/Nanopowders... 

The transport numbers of the ions can be determined by using a solid-state electrolyte. The cell voltage across an oxygen-conducting electrolyte subjected to an oxygen pressure gradient is given by the Nemst equation (Section 6.8.3) ... 

Figure 23. Proton conductivities of Y-doped BaZrtV65 and BaCeCV66 in comparison with the ion conductivity of the relevant solid oxygen ion electrolytes. Reprinted from K.D. Kreuer, St. Adams, W. Munch, A. Fuchs, U. Klock, and J. Maier, Solid State Ionics, 155 (2001) 295-306. Copyright 2001 with permission from Elsevier.

FIGURE 1.13 1 Low boundary of the oxygen-ionic conductivity for the solid (Zr02)o.9(Y203)o 1 electrolyte and 2 and the temperature dependence of logarithm pressure of dissociation for oxide Na20. (From Zhuiykov, S., Electron model of solid oxygen-ionic electrolytes used in gas sensors, Int. J. Applied Ceramic Techn. 3 (2006) 401-411. With permission.)... 

N.G. Torkelsen, and S. Raaen, Work function variations and oxygen conduction in a Pt/ZrC>2(Y203)/Pt solid electrolyte cell, Appl. Surf. Sci. 93, 199-203 (1996). 

In general Zr02 oxygen sensors consist of a tube-like solid-state Zr02 electrolyte where the electronic conductivity is based on oxygen ion charge carrier transport. The inner and outer surface of the yttrium-doped and stabilized zirconia tube is covered by porous platinum electrodes. 

For the purposes of review. Figure 1 illustrates the basic function of the cathode in a solid oxide fuel cell. Whether acting alone or as part of a stack of cells, each cell consist of a free-standing or supported membrane of an oxygen-ion-conducting electrolyte, often yttria-stabilized zirconia (YSZ). Oxygen, which is fed (usually as air) to one side of the membrane, is reduced by the cathode to oxygen ions via the overall half-cell reaction... 

Many oxygen ion conducting electrolytes are available for sensor applications. These include mainly solid solutions of Zr02, HFO, Th02, or CeO. Of these, stabilized zirconia has been found to have the best combination of cost, mechanical, chemical, and electrical properties for this type of application and has been the most widely used. Various stabilizers are available and have a strong effect on the properties obtained, particularly the electrical conductivity. 

Solid Oxide (SOFC) These cells use a solid oxygen-ion-conducting metal oxide electrolyte. They operate at about 1000 °C, with an efficiency of up to 60%. They may find application in industrial and large-scale applications. 

Oxygen anion conductors solid electrolyte Oxygen, chemisorbed - chemisorption of oxygen Oxygen conducting solid electrolyte - solid electrolyte... 

PEM technology was originally developed as part of the Gemini space program.16 In a PEM electrolyzer, the electrolyte is contained in a thin, solid ion-conducting membrane rather than the aqueous solution in the alkaline electrolyzers. This allows the H+ ion (proton) or hydrated water molecule (HsO+) to transfer from the anode side of the membrane to the cathode side, and separates the hydrogen and oxygen... 

The system (Figure 12) is based on sulfuric acid (H2SO4) synthesis and decomposition process (the Westinghouse process) developed earlier. The sulfur trioxide (SO3) decomposition process is facilitated by electrolysis with ionic oxygen conductive solid electrolyte to reduce the operation temperature 200°C-300°C lower than the Westinghouse process. 

Only 7.8% SO3 thermally decomposes in equilibrium condition at 500°C as shown in Figure 1, and also only about 20% in the case membrane reactor technique is used to increase decomposition fraction of SO3 at 500°C. Therefore, some other energy is required to obtain higher decomposition fraction of SO3. Electrolysis by ionic oxygen conductive solid electrolyte is applied to increase decomposition fraction of SO3 in HHLT. HHLT is composed of the reactions shown below. 

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