Résumé
Crystallized fast-alkaline conductors have promising properties for ion electrochemical sensors. Their conductivity at room temperature is very high (about 10
−4–10
−3 S cm
−1). The selectivity effect of such membranes is based on the calibration of conductive sites in the structure. NASICON materials are good examples from this point of view. Suitable cationic substitutions allow to adjust the size of the conduction sites and then to improve the selectivity effect. Recent experimental results on Na
+ and Li
+ membranes are shown in this field.