Synthesis and characterization of LLZNO & LLZTO: Insights into the impact of different lithium precursors on properties

Garnet-type Li₇La₃Zr₂O₁₂ (LLZO) is a promising solid electrolyte for all-solid-state batteries due to its high ionic conductivity and excellent thermal stability. However, production of high performance LLZO remains constrained by the reliance on high-purity reagents and complex synthesis routes. This study presents a cost-effective strategy to prepare high-performance Ta- and Nb-doped LLZO using commercially sourced raw materials via conventional solid-state reaction. Two lithium precursors, Li₂CO₃ and LiOH·H₂O, were systematically compared to evaluate their impacts on formation and performances of LLZO. LiOH-derived powders showed higher phase purity and finer morphology, while Li₂CO₃-derived powders offered better processability. While the LLZNO-LOH sample achieved 94.4% relative density and 0.78 × 10⁻³ S/cm conductivity, LLZTO-LCO also reached 0.75 × 10⁻³ S/cm with a relative density of 94.1%. All sintered samples exhibited phase-pure cubic garnet structures. These findings demonstrate the industrial feasibility of LLZO production, paving the way for its practical deployment in next-generation solid-state batteries.