Structural, Electrical, and Lithium Ion Dynamics of Li₂MnO₃ from Density Functional Theory

The layered Li₂MnO₃ is investigated by using the first-principles calculations within the GGA and GGA+U scheme, respectively. Within the GGA+U approach, the calculated intercalation voltage (ranges from 4.5 V to 4.9 V) is found to be in good agreement with experiments. From the analysis of electronic structure, the pure phase Li₂MnO₃ is insulating, which is indicative of poor electronic-conduction properties. However, further studies of lithium ion diffusion in bulk Li₂MnO₃ show that unlike the two-dimensional diffusion pathways in rock salt structure layered cathode materials, lithium can diffuse in a three-dimensional pathway in Li₂MnO₃, with moderate lithium migration energy barrier ranges from 0.57 to 0.63 eV.