Ion Conductivity Enhancement in Anti‐Spinel Li 3 OBr with Intrinsic Vacancies

Solid electrolytes are expected to play an important role in modern electrochemical energy storage technologies. However, it is still very challenging to achieve a high Li‐ion conductivity in solid electrolytes. In this study, an intrinsic vacancy induced ion conductivity enhancement in a recently synthesized anti‐spinel structure of Li 3 OBr compared with its anti‐perovskite phase is reported. With a high stability, the intrinsic defective structure of anti‐spinel Li 3 OBr contains a high concentration of octahedral vacancies. Ab initio molecular dynamic simulations confirm that octahedral vacancies can lead to an extraordinarily high Li mobility (0.136 mS cm −1 at room temperature) in anti‐spinel Li 3 OBr. Such an ion conductivity enhancement mechanism opens a new avenue in solid electrolyte material design.