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 (MnLi). In this work, we study the energetics and electronic properties involving MnLiin Li2MnO3through first-principles calculations. We find that MnLican reduce the formation energy of Li vacancies around it, but increase that of O vacancies, indicating that MnLicould suppress the release of O around it and facilitate capacity retention. Both O and Mn near the MnLican participate in charge compensation in the delithiation process. Furthermore, the effect of MnLion the migration of Li and Mn is investigated. All possible migration paths are considered and it is found that MnLimakes 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 MnLimakes further contribution to understand the relationship between intrinsic defects and electrochemical properties of Li2MnO3.