A model for modulating oxide ion transport with endo-particles for application in energy conversion

Certain energy conversion processes are underpinned by the transport of oxide ions across materials, components or interfaces. Examples include solid oxide fuel cells for power generation from hydrogen, but also chemical looping for hydrogen and syngas generation. Identifying new ways of enhancing oxide ion transport is thus required for advancing such technologies. Traditionally, this is achieved by doping or crystal lattice engineering but recent reports in these fields suggest a new approach, where oxide ion transport is potentially modulated through embedded (endo-) nanoparticles. This is assumed to occur due to the strain that endo-particles induce throughout the material. Here we propose a model to rationalize this effect, by constructing corresponding visual and numerical models of these experimental systems and calculating their respective volumetric strain and resulting conductivity enhancement. Our model indicates a strong correlation between ion conductivity enhancement and observed experimental data in these two different applications. This result demonstrates how nanoparticles may be harnessed within materials, to modulate oxide ion transport properties, beyond their traditional role as catalytic centers, which could inspire the design of new nanostructured oxide ion conductors for energy conversion applications.