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

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 degrees 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 degrees C by a simple synthesis method of wet mechanical milling. The cubic Li2OHCl prepared by this method performs an ionic conductivity of 4.27 x 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 degrees C. Moreover, it can still remain cubic phase after heat treatment at 210 degrees C. This work delivers a huge potential of fabricating high ionic conductivity phase anti-perovskite solid-state electrolyte materials by wet mechanical milling.