Mixed conductors

Mixed conductors are materials with a significant fraction of ionic as well as electronic conduction. This mixed conduction allows for the transport of a formally neutral species in a solid (e.g. oxygen in SrTiO₃) and is a prerequisite of many kinetic phenomena. Electrode materials (in batteries as well as in solid oxide fuel cells) are typically mixed conductors, and also oxidation catalysts often exhibit electronic as well as ionic conductivity.

Examples of mixed conductors investigated are:

SrTiO₃, TiO₂,
(La,Ba,Sr)(Mn,Fe,Co)O_3-d, La₂CuO_4+d,
CeO₂,
Li(Fe,Mn)PO₄

Current Projects:

• Size effects in nanocrystalline SrTiO₃
• Interface effects on the electrical conductivity of oxide thin films
• Concentration and mobility of protons in H⁺-SOFC cathode materials
• Formation and migration of oxygen vacancies in (La,Ba,Sr)(Co,Fe)O_3-δ perovskites
• Defect chemistry of alkali peroxides
• Defect chemistry of the LiFePO₄/FePO₄ redox couple
• Interfacial Li-storage phenomena in nanoporous anatase TiO₂ electrodes
• Concentration and mobility of protons in H⁺-SOFC cathode materials