Synthesis and characterization of Li7La3Zr2O12 via a novel solid-liquid route

Abstract

Polycrystalline cubic Li6.5Al0.22La3Zr1.93O11.94 (LLZO) with garnet structure has been synthesized by solid-liquid method (SLM) with acrylic acid as organic complexing agent, and acetate sol coated nano-ZrO2 powders as template. The polymeric precursors are characterized by means of TG/DTA, the resultant powders and sintered LLZO pellets are characterized by ICP-OES, X-ray diffraction (XRD), scanning electron microscopy (SEM) and impedance spectroscopy. It is shown that the morphology of the powders is dependent on the preparation conditions such as molar ratio of acrylic acid to metallic ions (L/M) and the pH values. Prepared powders are purity, single phase, an ellipsoidal shape and a particle size of 2–4 μm with good neck connection. The ionic conductivity of sintered LLZO pellets at 1100 °C for 6 h at room temperature is 3.09 × 10−4 S cm−1 and the relative density is 94.1%. The solid-liquid method can lower the sintering temperature, greatly shortens holding time, and gets relatively good the ionic conductivity and it is suitable for mass synthesis of high performance LLZO powders with the advantages of less amount of organic reagent and friendly environment.