Effects of lithium precursor and sintering strategy on the performance of LLZNO thin solid electrolytes

This work systematically investigates how lithium precursor and sintering strategy determine the processing–structure–property relationship of Nb-doped Li 7 La 3 Zr 2 O 12 (LLZNO) thin solid electrolytes. LLZNO thin electrolytes were fabricated by tape casting using a designed constrained-sintering methodology. A clear precursor-dependent evolution from powder characteristics to final microstructure and performance was identified. LiOH-derived powder showed more uniformly distributed particles with weaker agglomeration, enabling tighter packing and more homogeneous particle networks in the green tape. Consequently, the resulting thin electrolytes exhibited stable densification and similar ionic conductivities of 0.31–0.32 × 10 −3 S/cm at relative densities of ∼90–91%, regardless of sintering route. In contrast, Li 2 CO 3 -derived powder showed poorer particle contact and more heterogeneous packing, leading to non-uniform densification, lower ionic conductivities of 0.13–0.24 × 10 −3 S/cm at comparable densities, and greater sensitivity to the debinding–sintering routes. Overall, these findings provide insights into scalable fabrication of high-performance LLZO thin electrolytes.