Synthesis and Na+ conduction properties of Nasicon-type glass-ceramics in the system Na2O-Y2O3-X2O3-SiO2 (XÂ =Â B, Al, Ga) and effect of Si substitution

Glass-ceramics of the boron-, aluminium- or gallium-containing Na5RSi4O12-type (R = rare earth; Y) Na+-superionic conductors were prepared by crystallization of glasses with the composition Na3 + 3x + yY1−xXySi3−yO9 (X = B; NaYBSi, X = Al; NaYAlSi, X = Ga; NaYGaSi) (x = 0.2, y = 0.1). The crystallization kinetics of the glasses was examined by DTA, and the effects of X elements on the separation of the phase and the microstructural effects on the conduction properties of glass-ceramics were discussed. The activation energies of crystal growth of the NaYBSi, NaYAlSi and NaYGaSi glasses with the Na3.7Y0.8B0.1Si2.9O9, Na3.7Y0.8Al0.1Si2.9O9 and Na3.7Y0.8 Ga0.1Si2.9O9 compositions were 410, 392 and 382 kJ/mol, respectively. The conductivities of the glass-ceramic NaYBSi, NaYAlSi and NaYGaSi were 4.32 × 10− 2, 3.73 × 10− 2 and 3.40 × 10− 2 S/cm at 300 °C, respectively.