Influence of dry‐ and wet‐milled LLZTO particles on the sintered pellets

Abstract A Ta‐doped Li 7 La 3 Zr 2 O 12 (LLZTO) solid electrolyte is a promising candidate for all‐solid‐state lithium battery due to its high ionic conductivity and stability against lithium metal. In this work, physicochemical properties of both dry‐ and wet‐milled LLZTO particles were investigated. Based on X‐ray diffraction, Fourier transform–infrared, thermogravimetric analysis, and scanning electron microscopy results, it was confirmed that highly reactive LLZTO powder prepared in dry milling conditions exhibited faster size reduction, rougher surface morphology, fewer surface impurities, and less agglomerated particles, in contrast to those in wet milling conditions. Sintering these dry‐milled powders at 1320°C for 10 min in the air via solid‐state reaction produced dense ceramic pellets with a relative density of 97.4%. The room‐temperature ionic conductivity for LLZTO pellet via the dry milling was determined to be 6.94 × 10 −4 S cm −1 . Li–sulfur batteries based on the pellets showed an initial discharge capacity of 1301 mA h g −1 and a coulombic efficiency of 99.82% when cycled at room temperature. The effect of the milled powder on the sintered pellets was discussed in terms of boundary mobility, pore mobility, and morphology.