Wet Mechanical Milling Induced Phase Transition to Cubic Anti-Perovskite Li2OHCl

Abstract

Anti-perovskite solid-state electrolyte Li2OHCl usually exhibits orthorhombic phase and low ionic conductivity at room temperature. However, its ionic conductivity increases greatly when the temperature is up to 40 °C, while it goes through an orthorhombic-to-cubic phase transition. The cubic Li2OHCl with high ionic conductivity is stabilized at room temperature and even lower temperature about 10 °C by a simple synthesis method of wet mechanical milling. The cubic Li2OHCl prepared by this method performs an ionic conductivity of 4.27 × 10−6 S/cm at room temperature, about one order of magnitude higher than that of the orthorhombic Li2OHCl. The phase-transition temperature is decreased to around 10 °C. Moreover, it can still remain cubic phase after heat treatment at 210 °C. This work delivers a huge potential of fabricating high ionic conductivity phase anti-perovskite solid-state electrolyte materials by wet mechanical milling.