NASIGLAS structure and properties

ZrO2-deficient compositions of NASICON (Na1+xZr2−x/3SixP3−xO12−2x/3 where 0⩽x⩽3) have been prepared in glassy form (sodium superionic conducting glass (NASIGLAS)) using the melt quench method. The corresponding glass-ceramics have also been produced by heat treatment at appropriate temperatures identified from DTA. From 29Si MAS NMR, it is found that [SiO4] tetrahedra are predominantly Q2 species for composition x=3.0, but are mixed Q2–Q3 for x<3. Crystalline Na2ZrSi2O7 is found in all the corresponding glass-ceramic samples. The complex plane impedance method was used to determine the conductivity of NASIGLAS, which appears to be a complex function of mobility and concentration of Na+. 23Na NMR indicates anomalous motion when x=2.5. Low solubility of ZrO2 is noticeable in glasses with low value of x.