Max Planck Institute for Solid State Research

Solution of the three-carrier problem: A natural explanation for surprising observations

Authors

D. Poetzsch, R. Merkle, and J. Maier

Departments

Physical Chemistry of Solids (Joachim Maier)

The complex kinetics of stoichiometry changes in materials with three mobile carriers is analyzed and the "three-carrier problem" solved in the framework of linear irreversible thermodynamics. Numerical simulations predict and verify the experimentally observed decoupled hydrogen and oxygen diffusion in mixed conducting oxides upon an increase of water partial pressure. This ansatz supplies the tools to naturally explain non-monotonicities, apparent uphill diffusion and "moving boundary phenomena" in three carrier systems.

For the full text, see the German version.

Corresponding author

Rotraut Merkle

R.Merkle@...

Max Planck Institute for Solid State Research

References

Yu, J. H.; Lee, J. S.; Maier, J.

Peculiar Nonmonotonic Water Incorporation in Oxides Detected by Local In Situ Optical Absorption Spectroscopy Water incorporation in oxides: A moving boundary problem.

Angewandte Chemie International Edition 46, 8992-8994 (2007);

Solid State Ionics 181, 154-162 (2010)

Poetzsch, D.; Merkle, R.; Maier, J.

Stoichiometry variation in materials with three mobile carriers - thermodynamics and transport kinetics exemplified for protons, oxygen vacancies and holes.

Advanced Functional Materials 25, 1542–1557 (2015)

C1: This is the decisive difference between the present approach and an earlier approach (Yoo, H. I.; Yoon, J. Y.; Ha, J. S.; Lee, C. E.: Hydration and oxidation kinetics of a proton conductor oxide, SrCe_0.95Yb_0.05O_2.975) which leads to an inadequate description of the transport behavior.