Solid electrolyte oxygen diffusion

Diets H (1982) Gas-diffusion-controlled solid-electrolyte oxygen sensors. Solid State Ion 6(2) 175-183... 

Inorganic membranes can be categorized as shown in Table 2.1. The dense inorganic membranes consist of solid layers of metals (Pd, Ag, alloys) or (oxidic) solid electrolytes which allow diffusion of hydrogen (or oxygen). In the case of solid electrolytes transport of ions takes place. Another category of dense membranes consist of a porous support in which a liquid is... 

At the measurement electrode/solid electrolyte layer interface, the mass of Op gas which diffuses from the porous protective layer is equal to the mass of O2 which changes to oxygen ion plus the mass of CO gas which diffuses from the porous protective layer. (j), At the measurement electrode/solid electrolyte layer interface,... 

We will see that in the steady state of the blocking cells, we can extract partial conductivities, and from the transients chemical diffusion coefficients (and/or interfacial rate constants). Cell 7 combines electronic with ionic electrodes here a steady state does not occur but the cell can be used to titrate the sample, i.e., to precisely tune stoichiometry. Cell 1 is an equilibrium cell which allows the determination of total conductivity, dielectric constant or boundary parameters as a function of state parameters. In contrast to cell 1, cell 2 exhibits a chemical gradient, and can be used to e.g., derive partial conductivities. If these oxygen potentials are made of phase mixtures212 (e.g., AO, A or AB03, B203, A) and if MO is a solid electrolyte, thermodynamic formation data can be extracted for the electrode phases. 

The driving force for the diffusion of across the solid electrolyte membrane is the difference in O2 concentration between the anode and cathode side. This difference is a result of depletion of O2 by partial oxidation of CzHe on the anode side. Since the concentration of oxygen in the anode has a profound effect on the concentration gradient of 0 across the electrolyte membrane, the flow pattern of fuel/air mixture around the fuel cell has to be carefully controlled through the flow geometry. 

Discharge of oxygen ions on the gas-electrolyte surface with the following electron withdrawal (holes admission) on the surface layer of solid electrolyte and the removal of molecular oxygen from the surface of the electrolyte as a result of desorption (see Figure 1.18, < () It is also possible that the diffusion on the gas-metal interface can take place, with desorption following. 

Zhuiykov, S., Talanchuk, P., and Shmatko, B.A., Solid electrolyte sensor for measurement of the oxygen diffusion coefficients in melts, Herald of the Kiev Polytech. Inst. Instrumentation 22 (1992) 49-55. 

Given that mullite is a defect structure, one would expect high ionic conductivity. Rommerskirchen et al. have found that mullite has ionic conductivity superior to that of the usual CaO-stabilized Zr02 solid electrolytes at temperatures from 1,400 to 1,600°C [52], The oxygen self diffusion coefficient in the range 1,100 single crystal of 3 2 mullite has been given by [53] ... 

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