Interfacial protonic conduction in ceramics

Review on nanoperovskites: materials, synthesis, and applications for proton and oxide ion conductivity

“…[22], in nanocrystalline materials, interfacial protonic conduction is more considerable. As the grain size reaches nanoscale, the portion of the grain boundaries will be increased significantly in order that the overall ionic conduction of the nanocrystallite is controlled by electrical charge carrier concentrations and mobilities at the interface [22]. The nanoperovskite is a kind of promising material with particular physical and chemical characteristics resulting from its small particle size and large specific surface area.…”

“…It was proved that in certain cases oxygen ionic conductivity is enhanced by nanostructures [22,[94][95][96][97][98]. A move toward new ionic conductors for conductivity applications would be by making use of their active areas such as the grain boundary and surface.…”

“…Furthermore, in contrast to micrometer grains with a well-relaxed surface, nanograins are considered to involve a disordered surface structure and resultant dangling bonds, which lead to increased instability of the bare surface. This will modify the Lewis/Bronsted acidity of the hydroxyls and H 2 O molecules on the surface, leading to particular protonics behavior of such nanograined materials [22]. Miyoshi et al [106] measured the water uptake and conductivity property of nanograined yttria-doped zirconia fabricated by ultra-high pressure compaction at room temperature.…”

“…Recently, nanostructured materials having high protonic conductivity have been employed for various applications. In certain cases, oxygen ionic conductivity is also enhanced by synthesizing them as nanostructured materials [22]. Ionic conduction and protonic conduction in oxides at higher temperatures are important functional properties in tantalizing alternative processes for a cleaner conversion of chemical energy to electricity such as in solid oxide fuel cells (SOFCs), hydrogen gas separation membranes, solid oxide electrolyser cells (SOEC), etc.…”

Synthesis of inside-out core–shell perovskite-type oxide nanopowder

“…It may also incorporate internal pn junctions (at the core-shell interface), as discussed elsewhere for titanate-perovskites [24] which are expected to exhibit similar defect chemistry as cerate-perovskites. This may provide several interesting physical, chemical and electrical phenomena such as enhanced charge carrier concentration at the grain boundaries leading to improved conductivity [25][26][27][28][29][30]. In order to achieve such space charge regions one must, however, dope the perovskite crystal with donors.…”