Liquid phase penetration sintering of garnet-type solid electrolyte LLZTO

Abstract

Developing processes for manufacturing all-solid-state batteries that form ionic–conductive interfaces at low temperatures is crucial. In this study, dense ceramics garnet-type lithium ionconductors, Li6.5La3Zr1.5Ta0.5O12 (LLZTO) were prepared at low temperatures (500–800 °C) by reactive liquid phase penetration sintering (LPPS). In this process, pressed precursor oxides (La3Zr1.5Ta0.5O8.75) were exposed to the melt of lithium hydroxide monohydrate (LiOH·H2O). The garnet-type lithium ion conductor prepared by LPPS at 800 °C exhibited a total lithium ion conductivity of 2 × 10−4 S cm−1 at 25 °C. The prepared sample has a garnet crystalline network structure containing amorphous LiOH. The activation energy required for lithium-ion conduction of LLZTO prepared by the LPPS method (0.41 eV) is consistent with that of samples prepared by the conventional solid-phase sintering method at higher temperatures.