Ruthenium doped cubic-garnet structured solid electrolyte Li7La3Zr2-xRuxO12

The cubic garnet solid electrolyte Li7La3Zr2O12(LLZO) is recognised as a promising solid electrolyte for the all solid-state batteries. In this study, an effect of Ru doping to Zr site on electrochemical properties of the cubic LLZO is examined. The Ru-doped LLZO is prepared by a conventional solid-state reaction using Ga as a stabilise agent for the cubic phase. X-ray diffraction, scanning electron microscopy, and electrochemical impedance are used to characterise it. A lattice constant of the Ru-doped LLZO decreases with increase in doping amount of Ru. Also, a formation of perovskite LaRuO3 is confirmed in the Ru-doped LLZO. The Li ion conductivity of the Ru-doped LLZO is higher than that of the pure LLZO. The highest ionic conductivity of 2.56 x 10(-4) S/cm was obtained in Li7La3 Zr1.6Ru0.O-4(12). A promotion of sintering and shrinkage of lattice constant by the Ru doping would be reason for the improvement of Li ion conductivity in the Ru-doped LLZO.