Fast-ion conductor

As solid electrolytes they allow the movement of ions without the need for a liquid or soft membrane separating the electrodes.

Solid electrolytes find use in all solid-state supercapacitors, batteries, and fuel cells, and in various kinds of chemical sensors.

Proton conductors are a special class of solid electrolytes, where hydrogen ions act as charge carriers.

The most famous example of advanced superionic conductor-solid electrolyte is RbAg4I5 where σi > 0.25 Ω−1 cm−1 and σe ~10−9 Ω−1 cm−1 at 300 K.[1][2] The Hall (drift) ionic mobility in RbAg4I5 is about 2×10−4 cm2/(V•s) at room temperatures.

[3] The σe – σi systematic diagram distinguishing the different types of solid-state ionic conductors is given in the figure.

[8] Unlike the usual forms of alumina, this modification has a layered structure with open galleries separated by pillars.

Sodium ions (Na+) migrate through this material readily since the oxide framework provides an ionophilic, non-reducible medium.

Lehovec's effect is used as a basis for developing nanomaterials for portable lithium batteries and fuel cells.

Classification of solid-state ionic conductors by the lg (electronic conductivity, σ e ) – lg (ionic conductivity, σ i ) diagram. Regions 2, 4, 6 and 8 are solid electrolytes (SEs), materials with σ i ≫ σ e ; regions 1, 3, 5 and 7 are mixed ion-electron conductors (MIECs). 3 and 4 are superionic conductors (SICs), i.e. materials with σ i > 0.001 Ω −1 cm −1 . 5 and 6 are advanced superionic conductors (AdSICs), where σ i > 10 −1 Ω −1 cm −1 (300 K), energy activation E i about 0.1 eV. 7 and 8 are hypothetical AdSIC with E i ≈ k B T ≈0.03 eV (300 К).