Lowering the sintering temperature of Li<sub>7</sub>La<sub>3</sub>Zr<sub>2</sub>O<sub>12</sub> electrolyte for co-fired all-solid-state batteries via partial Bi substitution and precise control of compositional deviation

Li7La3Zr2O12 (LLZ) has great potential as a solid electrolyte for co-fired all-solid-state Li-ion secondary batteries. However, to realise solid-state battery using LLZ, the sintering temperature of LLZ should be reduced one that can suppress formation high-resistance reaction layer at interface between and electrode. In this study, we demonstrate an effective method reducing Li6La3ZrTaO12 by combining partial Bi-substitution Ta precise control compositional deviation. The intentional tuning La deficiency in Li6La3ZrTa0.8Bi0.2O12 (LLZTB0.2) promoted liquid phase based on Li2O–Bi2O3 grain boundary, resulting its densification 775 °C. Furthermore, fabricated half-cell LLZTB0.2 attached LiCoO2 + composite electrode operated 60 From these results, it was found proposed concept is applicable co-firing battery.