Wikipedia
Nanoionics is the study and application of phenomena, properties, effects and mechanisms of processes connected with fast ion transport (FIT) in all-solid-state nanoscale systems. The topics of interest include fundamental properties of oxide ceramics at nanometer length scales, and fast ion conductor ( advanced superionic conductor)/electronic conductor heterostructures. Potential applications are in electrochemical devices ( electrical double layer devices) for conversion and storage of energy, charge and information. The term and conception of nanoionics (as a new branch of science) were first introduced by A.L. Despotuli and V.I. Nikolaichik (Institute of Microelectronics Technology and High Purity Materials, Russian Academy of Sciences, Chernogolovka) in January 1992.
A multidisciplinary scientific and industrial field of Solid state ionics, dealing with ionic transport phenomena in solids, considers Nanoionics as its new division. Nanoionics tries to describe, for example, diffusion&reactions, in terms which make sence only at a nanoscale, e.g., in terms of non-uniform (at a nanoscale) potential landscape.
There are two classes of solid state ionic nanosystems and two fundamentally different nanoionics: (I) nanosystems based on solids with low ionic conductivity, and (II) nanosystems based on advanced superionic conductors (e.g. alpha– AgI, rubidium silver iodide–family). Nanoionics-I and nanoionics-II differ from each other in the design of interfaces. The role of boundaries in nanoionics-I is the creation of conditions for high concentrations of charged defects (vacancies and interstitials) in a disordered space-charge layer. But in nanoionics-II, it is necessary to conserve the original highly ionic conductive crystal structures of advanced superionic conductors at ordered (lattice-matched) heteroboundaries. Nanoionic-I can significantly enhance (up to ~10 times) the 2D-like ion conductivity in nanostructured materials with structural coherence, but it is remaining ~10 times smaller relatively to 3D ionic conductivity of advanced superionic conductors.
The classical theory of diffusion and migration in solids is based on the notion of a diffusion coefficient, activation energy and electrochemical potential. This means that accepted is the picture of a hopping ion transport in the potential landscape where all barriers are of the same height (uniform potential relief). In spite of the obvious difference of objects of Solid state ionics and nanoionics-I, -II, the true new problem of fast ion transport and charge/energy storage (or transformation) for these objects ( fast ion conductors) has a special common basis: non-uniform potential landscape on nanoscale (for example ) which determines the character of the mobile ion subsystem response to an impulse or harmonic external influence, e.g. a weak influence in Dielectric spectroscopy (impedance spectroscopy).