Preparation And Properties Of NASICON Monovalent Cation Conductors

In the process of preparing the solid electrolyte,the electrical conductivity can be improved by the means of adding sintering aids and doping.The sintering aid mainly improves the conductivity by improving the sintering performance and the density of the solid electrolyte.Doping improves the conductivity of the electrolyte by changing the size of the ion channel of the solid electrolyte and changing the binding energy between the framework and the conducting ions.Lithium ion solid electrolyte Li_1.3Al_0.3Ti_1.7?PO₄?₃ was prepared by high temperature solid phase method.The effect of Li F sintering aid on the preparation and properties of electrolyte was studied.When Li F is added at 1 wt%,the sample has the highest conductivity at room temperature,about 4.57×10^-4 S/cm.Through the study of the sensor,the sensor has the best reversibility and a large response value at 400 °C.The response value to 20000 ppm carbon dioxide is 48.2 m V,and the response time is 5.3 min.The O ion in the solid electrolyte Na_3.2Hf₂Si_2.2P_0.8O₁₂ was partially replaced by the F ion,and the solid electrolyte Na_3.2Hf₂Si_2.2P_0.8O₁₂-x F2x?x=0?0.3?with the NASICON structure was obtained.As the doping amount increases,the conductivity increases firstly and then decreases.When the doping amount of F is 0.15,the conductivity at room temperature of the solid electrolyte is the largest,being 2.36×10^-3 S/cm.The ion mobility at different temperatures measured by the DC polarization method is above 0.99,which proves that the solid electrolyte is mainly Na ion conduction.Nb was doped at the Si site of the solid electrolyte Na_3.2Hf₂Si_2.2P_0.8O₁₂,and a solid electrolyte Na_3.2-xHf₂Nb_xSi_2.2-xP_0.8O₁₂?x=0?0.3?with NASICON structure was obtained.When the doping amount of Nb is 0.2,the conductivity at room temperature of the solid electrolyte is the largest,which is 1.61×10^-3 S/cm.The ion mobility at different temperatures measured by the DC polarization method is above 0.99,which proves that the solid electrolyte is mainly Na ion conduction.Studying the effects of the sintering aid and doping on the properties of solid electrolytes provides new ideas for similar studies.Figure 32;Table 8;Reference 66...