Li_6.5La₃Zr_1.5−xBi_0.2Sb_0.3Sn_xO₁₂ as a novel solid electrolyte for sintered-type solid-state batteries

抄録

Sintered-type solid-state batteries (SSSBs) based on Li-ion-conductive oxides have attracted attention as the next generation of batteries, offering long lifetimes, high safety, and high energy density. The cubic garnet-type Li₇La₃Zr₂O₁₂ (LLZ) is a promising candidate for electrolyte materials of SSSBs. Its densification temperature is crucial for achieving SSSBs, as excessively high sintering temperatures lead to the formation of undesirable interphases between LLZ and electrode materials. This study reports new Li_6.5La₃Zr_1.5−xBi_0.2Sb_0.3Sn_xO₁₂ electrolytes with high sintering ability and high compatibility with metallic Li. The Sn substitution enhances sintering property, resulting in a lower densification temperature. On the other hand, the stability against Li metal decreases sharply as the Sn substitution level increases. Finally, Li_6.5La₃Zr_1.5Bi_0.2Sb_0.3O₁₂ and Li_6.5La₃Zr_1.3Bi_0.2Sb_0.3Sn_0.2O₁₂ exhibit good sinterability and high wettability and compatibility with Li metal, with a high Li-ion conductivity of 4.0 × 10⁻⁴ and 6.3 × 10⁻⁴ S/cm at 25 °C, respectively.