Formation of sodium ion conductive NaZr2(PO4)3 composite via liquid phase sintering method with sodium disilicate glass

NaZr2(PO4)3 (NZP) is one of the sodium superionic conductor (NASICON) groups with low thermal expansion. However, it was reported that has a very low ionic conductivity at room temperature. In this study, we tried to sinter the NZP with Na2Si2O5 glass to enhance the content of sodium ions and decrease the grain boundary resistance by the liquid-phase sintering method. The optimized ionic conductivity measured at room temperature was 8.9 x 10-6 S cm-1 with a highly dense cross-section. And the activation energy was also decreased to 0.42 eV, which is 84% of the pure NZP. Besides, both the bulk and grain boundary resistance decreased after adding the Na2Si2O5 glass. Herein, the synthesis of the solid electrolyte ceramics with selected glass materials via the liquid-phase sintering method can be considered to be an optimizable sinter method for improving the con-ductivity of the solid oxide electrolyte.