Influence of Indium-Tin Oxide Additive on the Sintering Process and Conductivity of Na₃Zr₂Si₂PO₁₂ Solid Electrolyte

Because of the poor sintering ability and low phase purity limit in the application of a Na₃Zr₂Si₂PO₁₂ solid electrolyte, it is important to find an effective way to obtain a pure and dense Na₃Zr₂Si₂PO₁₂ ceramic at reduced temperature. In this study, high conductive indium-tin oxide (ITO) was innovatively used as the sintering additive to improve the purity and density of the Na₃Zr₂Si₂PO₁₂ ceramic. The influence of ITO additive on density, phase, microstructure and conductivity of the Na₃Zr₂Si₂PO₁₂ ceramic was investigated. Archimedes method, x-ray diffraction, scanning electron microcopy and complex impedance spectroscopy were used as experimental techniques to evaluate the effect of the additive. The results show that the ITO sintering additive increases not only the purity and density but also the conductivity of the Na₃Zr₂Si₂PO₁₂ ceramic. The Na₃Zr₂Si₂PO₁₂ ceramic with 3 wt.% ITO additive sintered at 1150°C for 4 h possesses a high density of 3.15 g/cm³ and good conductivity of (3.95 ± 0.12) × 10⁻⁴ S/cm.