Effect of sintering temperature and holding time on the crystal phase, microstructure, and ionic conductivity of NASICON-type 33Na2O-40ZrO2-40SiO2-10P2O5 solid electrolytes.

33Na2O-40ZrO2-40SiO2-10P2O5 solid electrolytes were successfully prepared by the solid-phase reaction. The effects of sintering temperature and holding time on the crystal phase, microstructure, and electrical properties of the solid electrolytes were investigated by TG-DTG, X-ray diffraction (XRD), scanning electron microscope (SEM), infrared spectroscopy (IR), and electrochemical impedance spectroscopy (EIS). The results show that the main crystal phases of all the obtained solid electrolytes are Na3Zr2Si2PO12 of NASICON-type monoclinic structure, accompanied by a small amount of ZrO2 secondary phase. The sintering temperature and time have a significant effect on the microstructure of the materials but have little effect on the crystalline phases. The fine grain morphology and stable structure are beneficial to reduce the hindrance of ion conduction. These solid electrolytes sintered at 1200 °C for 15 h shows the highest room temperature ionic conductivity of 7.82 × 10–4 S·cm−1. At the same time, the good air stability of the solid electrolyte indicates that it has certain application prospects in the fields of gas sensors, portable electronic equipment, and so on. [ABSTRACT FROM AUTHOR]