Low-sintering-temperature garnet oxides by conformal sintering-aid coating

Abstract

Garnet-type solid electrolytes have attracted an extensive attention for high-energy solid-state lithium batteries. However, the high processing temperature up to 1200 °C with high cost limits the large-scale production. Here, we report a simple approach to reduce the sintering temperature 15 by a conformal coating of nanoscale amorphous alumina, without sacrificing ionic conductivity. The ceramic sintered at 980 °C shows a high ionic conductivity of 0.13 mS cm-1 at room temperature. It reveals that the second phases segregated at grain boundaries are ionically conductive but electronically blocking, which can block electronic conduction and improve mechanical property. The Li symmetry cells using this garnet electrolyte indicate a long-term 2