Low-Temperature Sintering of a Garnet-Type LiLaZrTaO Solid Electrolyte and an All-Solid-State Lithium-Ion Battery.

Garnet-type Ta-substituted LiLaZrO materials attract considerable attention as solid electrolytes for use in future oxide-based all-solid-state lithium-ion batteries owing to their superior ionic conductivity and chemical and electrochemical stabilities. However, high-temperature sintering above 1000 °C, which is needed to realize high lithium-ion conductivity, results in the formation of insulating interface impurities at the electrode-electrolyte interface. Herein, the low-temperature sintering of the LiLaZrTaO (LLZT) solid electrolyte at a remarkably low temperature of 400 °C was demonstrated using the submicrometer-sized garnet-type LLZT fine powder sample prepared at 600 °C through a reaction of LiO and LaZrTaO. The lithium-ion conductivity at 25 °C was 4.54 × 10 S cm without any additives through low-temperature sintering at 400 °C. In addition, the preliminary battery performance of the oxide-based all-solid-state LiNiCoMnO-LiTiO full-battery cell fabricated at 400 °C using the present LLZT fine powder sample as the solid electrolyte was demonstrated.