6.25M 0.25La 3Zr 2O 12 (M: Al 3+ and Ga 3+)]]>

摘要

AbstractThe sintering behavior and electrochemical properties of garnet-like Li6.25M0.25La3Zr2O12(M: Al3+and Ga3+) were investigated. The sintering of Li6.25Al0.25La3Zr2O12progressed at 1050°C. On the other hand, the densification of Li6.25Ga0.25La3Zr2O12pellets progressed at lower temperatures above 950°C to yield relative densities of 93.9% after sintering at 1000°C. The temperatures at which the sintering of Li6.25M0.25La3Zr2O12progressed are in good agreement with the temperatures where the liquid phases of Li-M-O compounds form. The sintering of these compounds was consistent with the change in the lattice parameter due to the replacement of Li+for Al3+/Ga3+in the structure. These results suggest that the cation diffusion between the grains and the grain boundaries due to the replacement of Li+for Al3+/Ga3+in the garnet-like structure improves the grain growth of these compounds. Dense pellets of Li6.25Ga0.25La3Zr2O12were obtained by sintering at 1000°C for 12h without the use of mother powders, and the bulk and total conductivities obtained at 25°C were 1.6×10?3and 9.6×10?4Scm?1, respectively. The activation energies for the bulk and total conductivities were 0.25 and 0.32eV, respectively. Li6.25Ga0.25La3Zr2O12was stable in contact with lithium metal, even for a long period of 1month.Highlights?The sintering of Li6.25Al0.25La3Zr2O12progressed at 1050°C.?The sintering of Li6.25Ga0.25La3Zr2O12progressed above 950°C.?The grain growth of these compounds is enhanced at temperatures where the liquid phases of Li-M-O compounds form.?