Research On The Preparation And Ion Doping Of Garnet Li₇La₃Zr₂O₁₂

All-solid-state battery has many advantages such as safe, environmental friendly,which has a higher energy density. The key to the study of solid-state battery is the solid electrolyte, and find a higher ionic conductivity, wider electrochemical window features and good stability of the solid electrolyte. Overall, compared with the solid electrolyte such as a polymer solid electrolyte and NASION etc. Li₇La₃Zr₂O₁₂（LLZO） material has great prospects for development in the synthesis of control, stability and other aspects that it can enhance and improve the electrical conductivity. Thus, LLZO material has great prospects in applications. Therefore, this paper explored the synthesis of LLZO material, improved and optimized the synthesis conditions, and obtained a high ion conductivity, explored its chemical and physical property of LLZO. Subsequently in order to improve the ionic conductivity of LLZO, it was further doped. and finally the solid electrolyte are loaded into battery, explored the its influencing factors.First, this paper studied LLZO material that was synthesized by solid-phase synthesis, explored the impact of LLZO synthetic materials by controling the milling process of milling time and changeing in pressure during tableting. SEM and EIS showed that precursor particles was uniform and dense when the milling time was 12 h and tableting pressure was 26 MPa. SEM showed that the solid electrolyte of LLZO materials had better density at 950 ℃. XRD also showed that the LLZO materials had the better degree of crystallinity and higher impurity phase at 950 ℃. Its AC impedance derived higher ionic conductivity, resulting in ionic conductivity of 4.27×10-7 S/cm.when sintering time was 18 h, the LLZO materials had better electrochemical properties.After achieving optimal sintering temperature and time, Ba and Ta are doped which could improve the ionic conductivity of the material LLZO. SEM and XRD showed that doped 2%Ba, 4%Ta and 6%Ta could improve the density and crystallinity of the material, resulting in ionic conductivity of 2.68×10-7 S/cm, 1.02×10-6 S/cm and1.42×10-6 S/cm respectively, at room temperature.This paper initially explored how to assemble the solid-state battery, and the effects of different LLZO solid electrolyte for the battery material on the electrochemical properties. In addition, measured the open-circuit voltage, electrochemical impedance and the charge-discharge capacityt doped with 4%Ba, 4%Ta and 6%Ta. However, there are some problems like the interfacial impedance between electrode material and the solid electrolyte LLZO, leading the polarization was too large. Making the open circuit voltage was less than 3 V, which had only 64% of the theoretical capacity. It still need tobe researched.