First-principles study of Mn antisite defect in Li₂MnO₃

Lithium-rich layered Li₂MnO₃is regarded as a new generation cathode material for lithium-ion batteries because of its high energy density. Due to the different preparation methods and technological parameters, there are a lot of intrinsic defects in Li₂MnO₃. One frequently observed defect in experiments is Mn antisite defect (Mn_Li). In this work, we study the energetics and electronic properties involving Mn_Liin Li₂MnO₃through first-principles calculations. We find that Mn_Lican reduce the formation energy of Li vacancies around it, but increase that of O vacancies, indicating that Mn_Licould suppress the release of O around it and facilitate capacity retention. Both O and Mn near the Mn_Lican participate in charge compensation in the delithiation process. Furthermore, the effect of Mn_Lion the migration of Li and Mn is investigated. All possible migration paths are considered and it is found that Mn_Limakes the diffusion energy barrier of Li increased, but the diffusion energy barriers of Mn from transition metal layer to Li layer are decreased, especially for the migration of the defect Mn. The insight into the defect properties of Mn_Limakes further contribution to understand the relationship between intrinsic defects and electrochemical properties of Li₂MnO₃.