LV Xiaojuan, LI Jing, ZHANG Feng, WANG Rui
(Department of Environmental Science and Engineering, North China Electric Power University (Baoding), Baoding 071000, Hebei, China)
Abstract: The liquid electrolytes in lithium ion batteries have serious problems, such as high flammability and possible explosion. Solid electrolytes are potential replacements for the liquid electrolytes, due to their high safety and stability. Among various inorganic solid lithium ion electrolytes, Li7La3Zr2O12 (LLZO) based electrolyte possesses bulk conductivity and grain boundary conductivity comparable with those of the liquid electrolytes, thus having great prospects in terms of improving conductivity and stability. In order to further improve its conductivity, LLZO was doped with SnO2 through the conventional ceramic processing. The LLZO samples were characterized by using XRD and AC impedance, while the ion activation energy was derived. The ionic conductivity of pure Li7La3Zr2O12 is 2.58×10-6 S/cm. The doping with Sn4+ stabilized the cubic phase of LLZO. The sample (Li7La3Zr1.7Sn0.3O12) with 0.3 Sn4+ had an ionic conductivity of 2.52×10-5 S/cm, which is higher than that of pure LLZO by about one order of magnitude.
Key words: Lithium ionic conductor; garnet; all solid electrolyte; ionic conductivity; doping