Polaron states and migration in F-doped Li2MnO3

Li2MnO3 compound is one essential component of the Li-rich solid solution cathode material (mLi2MnO3⋅nLiMO2, M = Mn, Ni, Co, etc.) for lithium ion batteries. The intrinsic insulating nature of the electronic structure determines that the electronic conductivity of the Li2MnO3 compound is low, which is unfavorable to the fast charge/discharge performance of the battery. In this paper, we demonstrate that F doping can create polaron states in the Li2MnO3 lattice from first principles calculations. The small polaron migration energy barrier in the Li2MnO3 lattice is about 0.27 eV. It is also observed that the polaron state is strongly trapped by the F atom, which decreases the efficiency of the doping enhanced electronic conductivity.