YANG Dunjie ，CHEN Fei，LI Junyang，ZHANG Yanghua，SHEN Qiang，ZHANG Lianmeng
(State Key Lab of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology,
Wuhan 430070, Hubei, China)
Abstract: All solid state lithium ion battery with high voltage, high energy density, and good safety performance is one candidate to replace the currently-used liquid electrolyte in the future in a wide range of consumer electronics, electric vehicles and grid energy storagesystems. In recent years, a novel class of inorganic ceramic solid electrolyte with garnet structure Li7La3Zr2O12, known as LLZO, has been developed. LLZO has two phases: cubic phase and tetragonal phase. The Li-ion conductivity for cubic phase which is available for application is ~ 10-3 S/cm, compared to ~ 10-6 S/cm for the tetragonal phase. To obtain the cubic phase, Al is necessary for the stability of the cubic phase calcined at high temperature by FAST. The morphology, ionic conductivity and conductivity of the existence form of Al3+ in the cubic LLZO were studied using FESEM, XRD, NMR and electrical impedance spectroscopy, respectively. The results show that the sample sintered at 1150 ℃ has a maximum relative density value of 99.8% and the highest ionic conductivity value is about 5.7×10-4 S/cm. and the NMR results show that the Al cation is located in the tetrahedrally coordinated 24 d site in cubic LLZO.
Key words: all solid state electrolyte; LLZO; FAST; ionic conductivity