Enhanced Li ion conductivity in Ge-doped Li0.33La0.56TiO3 perovskite solid electrolytes for all-solid-state Li-ion batteries

Ge-Doped Li 0.33 La 0.56 TiO 3 (Ge-LLTO) perovskites are synthesized with various GeO 2 contents by solid-state reactions as Li-ion conductive electrolytes for rechargeable all-solid-state Li batteries. After the addition of GeO 2 , the sinterability and Li ion conductivity are enhanced for the perovskite solid electrolyte. The Li 0.43 La 0.56 Ti 0.95 Ge 0.05 O 3 electrolytes exhibit the highest sinterability and Li ion conductivity among the as-prepared Li 0.33+2 x La 0.56 Ti 1− x Ge x O 3 electrolytes. The improvement of Li ion conductivity might be attributed to the improvement of the densification and structural integrity of the LLTO solid electrolyte. The lithium transference number ( t Li + ) of Ge-doped LLTO is close to 1. Moreover, the Ge-LLTO electrolytes are stable in the potential range of 0-10 V vs. Li/Li + . Ge-Doped Li 0.33 La 0.56 TiO 3 perovskites are synthesized by solid-state reactions and have been demonstrated as Li-ion battery solid electrolytes with excellent ion conductivity and electrochemical stability.