Sintering behavior of garnet-type Li7La3Zr2O12-Li3BO3 composite solid electrolytes for all-solid-state lithium batteries ☆

Abstract In this study, Li 3 BO 3 glass ceramic was utilized as a sintering additive for producing garnet-type Li 7 La 3 Zr 2 O 12 solid electrolytes by low temperature sintering. The shrinkage and wetting behaviors of the Li 7 La 3 Zr 2 O 12 -Li 3 BO 3 composite powder during heating were analyzed by dilatometry. The sintering shrinkage of the Li 7 La 3 Zr 2 O 12 -Li 3 BO 3 composite powder occurred in two stages and was related to the densification of the composite. It was also closely related to the wetting behavior of the Li 3 BO 3 glass. The sintering of Li 7 La 3 Zr 2 O 12 -Li 3 BO 3 from around 700 °C is driven by the viscous sintering of Li 3 BO 3 glass, while sintering above 850 °C is due to particle rearrangement in Li 7 La 3 Zr 2 O 12 as well as the solid-state sintering of Li 7 La 3 Zr 2 O 12 after the melting of Li 3 BO 3 . The density of the Li 7 La 3 Zr 2 O 12 -8 wt% Li 3 BO 3 composite sintered for 8 h at 1100 °C was 86.4% of the theoretical density, whereas the ionic conductivity was 1.94 × 10 − 5  S cm − 1 .