An advanced superionic conductor (AdSIC) in materials science, is a fast-ion conductor that has a crystal structure close to optimal for fast-ion transport (FIT).
The term was introduced in a paper by A.L. Despotuli, A.V. Andreeva and B. Rambaby.
The rigid ion sublattice of Advanced SuperIonic Conductors (AdSICs) has structure channels where mobile ions of opposite sign migrate. Their ion-transport characteristics display ionic conductivity of ~0.3/é cm (RbAg<sub>4</sub>I<sub>5</sub>, 300 K) and activation energy of E<sub>i</sub>~0.1 eV. This determines the temperature-dependent concentration of mobile ions ni~Ni x e<sup>Ei/kBT</sup> capable to migrate in conduction channels at each moment (Ni~10<sup>22</sup>/cm<sup>3</sup>, ni~2x10<sup>20</sup>/cm<sup>3</sup>, 300 K).
The Rubidium silver iodideâÂÂfamily is a group of AdSIC compounds and solid solutions that are isostructural with the RbAg<sub>4</sub>I<sub>5</sub> alpha modification. Examples of such compounds with mobile Ag<sup>+</sup>- and Cu<sup>+</sup>-cations include KAg<sub>4</sub>I<sub>5</sub>, NH<sub>4</sub>Ag<sub>4</sub>I<sub>5</sub>, K<sub>1âÂÂx</sub>Cs<sub>x</sub>Ag<sub>4</sub>I<sub>5</sub>, Rb<sub>1âÂÂx</sub>Cs<sub>x</sub>Ag<sub>4</sub>I<sub>5</sub>, CsAg<sub>4</sub>Br<sub>1âÂÂx</sub>I<sub>2+x</sub>, CsAg<sub>4</sub>ClBr<sub>2</sub>I<sub>2</sub>, CsAg<sub>4</sub>Cl<sub>3</sub>I<sub>2</sub>, RbCu<sub>4</sub>Cl<sub>3</sub>I<sub>2</sub> and KCu<sub>4</sub>I<sub>5.</sub>
RbAg<sub>4</sub>I<sub>5</sub> AdSIC displays peculiar features of crystal structure and dynamics of mobile ions.
Recently, all solid state micrometre-sized supercapacitors based on AdSICs (nanoionic supercapacitors) had been recognized as critical electron component of future sub-voltage and deep-sub-voltage nanoelectronics and related technologies (22 nm technological node of CMOS and beyond). Researchers also developed an all-solid-state battery employing RbAg<sub>4</sub>I<sub>5</sub> superionic conductor.