Defect Physics, Delithiation Mechanism, and Electronic and Ionic Conduction in Layered Lithium Manganese Oxide Cathode Materials

Optimizing batteries is a major theme in energy research, for which better electrode materials are needed. Li₂MnO₃ has long been considered for lithium ion batteries, yet its intrinsic delithiation mechanism is not well understood, and its practical performance remains poor. In this study, defect calculations reveal that, unlike in the related LiMnO₂, lithium release in Li₂MnO₃ involves oxidation at the oxygen site, not the manganese site, leading to bound oxygen-hole polarons. This insight into the unconventional mechanism indicates that nanostructuring and doping could yield high-capacity cathodes.