Oxides, defect chemistry perovskite type

The limits of integration are the oxygen partial pressures maintained at the gas phase boundaries. Equation (10.10) has general validity for mixed conductors. To carry the derivation further, one needs to consider the defect chemistry of a specific material system. When electronic conductivity prevails, Eqs. (10.9) and (10.10) can be recast through the use of the Nemst-Einstein equation in a form that includes the oxygen self-diffusion coefficient Dg, which is accessible from ionic conductivity measurements. This is further exemplified for perovskite-type oxides in Section 10.6.4, assuming a vacancy diffusion mechcinism to hold in these materials. 

The transport properties of perovskite-type oxides are dependent mainly on the B-site cations. Among them, Mn-based perovskites and Co/Fe-based perovskites are most frequently used for high-temperature and intermediate-temperature SOFCs, respectively. Recently, Ni-based K2NiF4-type oxides are also being investigated [5]. Their composition and microstructure are still to be optimized based on the defect chemistry, electrochemistry, and thermodynamics. 

Voorhoeve RJH, Remeika JP, Trimble LE. (1976). Defect Chemistry and Catalysis in Oxidation and Reduction over Perovskite-Type Oiddes. Ann Ny AcadSci. 272, 3-21. 

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