Electronic structure and lithium ion diffusion in Cr, Mo, W doped LiNiO2 for Li-ion batteries cathode material: First-principles study

Ni-rich cathode materials are among the most promising electrode materials for lithium-ion batteries due to their high capacity and low cost. Doping is considered to be one of the most effective strategies to mitigate cycling performance degradation and enhance the stability of the cathode material. In this study, group VIB transition metals (TM = Cr, Mo and W) were doped into pristine LiNiO₂, and their effects on structural stability, electronic properties, lithium-ion diffusion, and intercalation voltage were systematically investigated using density functional theory and ab initio molecular dynamics simulations. TM doping introduces impurity bands, reducing the band gap and significantly enhancing conductivity. The doped systems have thermodynamic stability. Both intrinsic and doped systems exhibit anisotropic diffusion, the b-axis remaining the energetically favored path for Li⁺ migration. The diffusion activation energy of lithium-ion along b-axis decreases from 0.996 eV (pristine) to 0.696 eV (Cr), 0.608 eV (Mo) and 0.611 eV (W). Mo/W-doped systems exhibit Li⁺ diffusion coefficients and rates 6 orders of magnitude higher than the pristine system. The intercalation voltage is also increased by TM-doped system. These results provide a theoretical foundation for optimizing Ni-rich cathodes through doping strategies, emphasizing the superior efficacy of Mo/W dopants in enhancing conductivity and Li⁺ transport.