Doping lithium-ion battery electrode materials $\mathrm{Li}M{\mathrm{O}}_2$ ($M=$ Co, Ni, Mn) with impurities has been shown to be an effective way to optimize their electrochemical properties. Here, we report a detailed first-principles study of layered oxides ${\mathrm{LiCoO}}_2$, ${\mathrm{LiNiO}}_2$, and ${\mathrm{LiMnO}}_2$ lightly doped with transition-metal (Fe, Co, Ni, Mn) and non-transition-metal (Mg, Al) impurities using hybrid-density-functional defect calculations. We find that the lattice site preference is dependent on both the dopant's charge and spin states, which are coupled strongly to the local lattice environment and can be affected by the presence of codopant(s), and the relative abundance of the host compound's constituting elements in the synthesis environment. On the basis of the structure and energetics of the impurities and their complexes with intrinsic point defects, we determine all possible low-energy impurity-related defect complexes, thus providing defect models for further analyses of the materials. From a materials modeling perspective, these lightly doped compounds also serve as model systems for understanding the more complex, mixed-metal, $\mathrm{Li}M{\mathrm{O}}_2$-based battery cathode materials.

• Received 8 August 2017
• Revised 24 October 2017

DOI:https://doi.org/10.1103/PhysRevMaterials.1.075403