Pushing Nanoionics to the Limits: Charge Carrier Chemistry in Extremely Small Systems

Size effects in ionic systems are of extraordinary importance for ion transport as well as mass storage. This constitutes the field of nanoionics. Even though the impact of size can be manifold, the interfacial symmetry break and its consequence of carrier redistribution is to the fore. The contribution goes beyond the mesoscopic case, where any contribution of unperturbed bulk defect structure has disappeared, and extrapolates into the regime of atomistic sizes. Even though these extrapolations represent pure thought experiments, much can be learned from them. They refer to the transition of heterolayered systems to layered crystals, of composites to mixed crystals as well as of nanocrystalline state to the amorphous state. Resulting effects on thermodynamics, transport and storage are discussed.