Effects of antimony tin oxide (ATO) additive on the properties of Na3Zr2Si2PO12 ceramic electrolytes

Abstract

Inorganic ceramic as one of the most promising candidate for solid state electrolytes (SSEs) have received extensive attention due to their excellent thermal stability, good electrochemical stability and wide electrochemical window. The sodium super ionic conductor (NASICON, Na3Zr2Si2PO12) structure possesses a three-dimensional network, which helps the migration of Na+. However, because of its low Na+ ion conductivity and poor sintering performance, Na3Zr2Si2PO12 is difficult to achieve application. Therefore, it is quite urgent to solve these questions. In this study, we have reported the effects of additive antimony-tin oxide (ATO) on the phase, microstructure and ionic conductivity of Na3Zr2Si2PO12 ceramic electrolytes. With the ATO sintering additive added, the Na+ ion conductivity and density of Na3Zr2Si2PO12 ceramic electrolytes were improved. The Na3Zr2Si2PO12 ceramic with 5 wt% ATO additive sintered at 1100 °C shows a relatively high ionic conductivity of 1.43×10−3 S cm-1 at room-temperature, most densest microstructure and wide electrochemical window up to 4.6 V (vs. Na/Na+). In addition, Na/NASICON/Na symmetrical cells were assembled and exhibited good cycling stability which implied good compatibility between sodium (Na) metal and NASICON electrolyte.