High-Pressure Synthesis and Lithium-Ion Conduction of Li4OBr2 Derivatives with a Layered Inverse-Perovskite Structure

Abstract

Li4OBr2, an n = 1 member of the inverse Ruddlesden–Popper (iRP) phase Li3n+1OnBrn+1, was prepared for the first time by high-pressure (HP) synthesis. The changes in the stability and the ionic conductivity induced by F or I substitution for Br were also investigated by density functional theory (DFT) calculations and were experimentally attempted as well. The experimentally observed activation energy of Li4OBr2 was 0.63 eV, which was further lowered by F or I substitution for Br or the introduction of Li–Br defects.