Exploring mesoscopic microstructural ordering in non-stoichiometric La2NiO4+d

La2NiO4+d is a performant oxygen ion conductor already at room temperature. During the electrochemical oxygen uptake/release reaction, a complex twin domain structure, anti-phase boundary domains and mesoscopic domain ordering is observed. The understanding of domain ordering for interface diffusion is mandatory to better understand diffusion processes at the interface. We propose here a controlled electrochemical reaction to explore in situ the formation of the domain structure and up to which extend domain sise and ordering periodicities depend on the current densities applied.