Effects of boron and phosphorus substitution on sodium-ion conduction properties of glass-ceramic Na5FeSi4O12

Abstract

This study has focused on the effect of Si-substitution with alio-valent boron and phosphorus on sodium-ion (Na+) conduction properties of the newly developed glass-ceramic Na5FeSi4O12. The glass-ceramics with the Na+conducting single phase were obtained with the compositions Na5+xFeBxSi4-xO12 and Na5-yFePySi4-yO12, although the solubility limits were restricted as x < 0.4 and y < 0.3. The conductivity of the mother Na5FeSi4O12glass-ceramics was enhanced on both Na5+xFeBxSi4-xO12 and Na5-yFePySi4-yO12, and the maximum conductivities were achieved on the compositions Na5.2FeB0.2Si3.8O12 (x = 0.2) and Na4.9FeP0.1Si3.9O12 (y = 0.1), as high as 3.1 × 10-3 and 4.2 × 10-3 S cm-1 at 300 °C, respectively.