High lithium ionic conductivity of garnet-type oxide Li7+xLa3Zr2-xSmxO12 (x = 0-0.1) ceramics

Li7La3Zr2O12 (LLZO) garnet is one of the most promising Lithium-ion solid electrolytes in all-solid-state Lithium-ion batteries, due to its higher chemical stability to Li metal and relatively higher lithium-ion conductivity. To further increase the electrical conductivity of LLZO, Sm3+ is doped into the Zr4+ site of LLZO so that excess Li occupies the position of the octahedral. Thereby lithium ion transport and increasing ionic conductivity are promoted. The optimal addition of Sm3+ is 0.06. Li7+xLa3Zr2-xSmxO12 (LLZSO, x = 0.06) electrolyte with cubic phase is obtained with sintering at 1200 °C for only 3 h. It has higher relative density and better ionic conductivity than the pristine LLZO. Its bulk and total ionic conductivity are ∼6.4 × 10−4 S·cm−1 and 2.46 × 10−4 S·cm−1 at 20 °C, respectively.