Synergistic regulation of garnet-type Ta-doped Li7La3Zr2O12 solid electrolyte by Li+ concentration and Li+ transport channel size. (10th February 2019)

• Record Type: Journal Article
• Authors: Zhang, Yanhua; Deng, Jiadong; Hu, Dongwei; Chen, Fei; Shen, Qiang; Zhang, Lianmeng; Dong, Shijie
• Is Part Of: Electrochimica acta. Volume 296(2019)
• Page Start: 823
• Page End: 829
• Publication Date: 2019-02-10
• Subjects: Solid electrolytes -- Li+ concentration -- Li+ transport channel size -- Synergistic regulation; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2018.11.136
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: The Li + concentration and Li + transport channel size of garnet-type solid electrolyte Li7 La3 Zr2 O12 are the two key factors associated with the improvement of Li ionic conductivity. Through precise control of the Li + concentration and the Li + transport channel size by Ta-doping (Li7-X La3 Zr2-X TaX O12, X = 0.2–1.0), synergistic regulation of the two factors is achieved. Results show that the optimum Li + concentration seems to be at about 6.31 where the Li + occupancy in LiO6 is high and the Li + arrangement in LiO4 is disordering. With the Li + concentration higher than 6.31, the occupancy in LiO4 sites remains constant but the Li + arrangement in LiO4 becomes more and more ordering. At higher Li + concentration of 6.52, Li + arrangement becomes certain of ordering which should have reduced the grain conductivity, however, the grain conductivity is still as high as 9.84 × 10 −4 S cm −1 . This indicates that LLZO with this Li + concentration have favorable Li + transport channel size. The optimum Li + transport channel size is about 12.95 ± 0.01 Å. At Li + concentration of 6.31, the proper Li + concentration is the main factor for the high grain ionic conductivity of 10.1 × 10 −4 S cm −1 . While at Li + concentration of 6.52, the suitable Li + transport channel size is the main factor for the high grain ionic conductivity. In conclusion, the high grain ionic conductivity at Li + concentration of 6.31–6.52 is due to the synergistic regulation of Li + concentration and Li + transport channel size.