Synthesis of single phase cubic Al-substituted Li7La3Zr2O12 by solid state lithiation of mixed hydroxides

Substituted Li7La3Zr2O12 (LLZ) with cubic garnet type structure is a promising candidate for solid state electrolyte in all-solid-state batteries. Here we present a novel synthesis route to obtain single phase cubic Al-substituted LLZ. The two step method consists of a co-precipitation of metal hydroxides from aqueous solution as well as solid-state lithiation and crystallization of the dried precipitate. Morphology and chemical composition of precipitated particles were investigated with SEM and EDS. Phase composition of calcined powder was confirmed to be pure phase cubic LLZ via XRD. The temperature dependent lithium ion conduction of a sintered pellet was determined to be 6.3 · 10−5 S/cm at 353 K with an activation energy of 0.58 eV.