Configurational Disorder, Strong Anharmonicity, and Coupled Host Dynamics Lead to Superionic Transport in LiYCl (LYC).

In superionic crystals, liquid-like ionic diffusivities often come hand-in-hand with ultra-low thermal conductivity and soft vibrational dynamics. However, generalized relationships between ion transport and vibrational dynamics remain elusive due to the diversity of superionic materials and complex underlying mechanisms. Here, the links between vibrational dynamics and ion transport in close-packed lithium halide ion conductor LiYCl (LYC) are examined using a suite of atomistic first-principles methods.