Lithium Antiperovskite-Derived Glass Solid Electrolytes

In this paper, we report the synthesis of Li₂OHX (X = Br, Cl)-based glasses. These glasses were found to be challenging to synthesize, requiring extreme cooling rates achievable only by a twin-roll quench process. As has been speculated for antiperovskite-derived glasses, indications of improved lithium-ion dynamics are observed. Notably, spin-lattice relaxation nuclear magnetic resonance spectroscopy reveals a higher hopping frequency and significantly lower activation energy for Li₂OHBr glasses (0.29 eV) compared to the crystalline Li₂OHBr (0.39 eV). This may be attributable to the increased free volume in the glass samples (ρ_glass/ρ_cryst = 0.83) and a reduced ionic interaction of lithium ions with the glass structure. Despite these promising findings, the glasses were found to be unstable under pressure and crystallized in attempts to produce bulk samples for impedance measurements.