On the first principles of Ti-doped LiNiO₂

Based on density functional theory, the first principles supersoft pseudopotential plane wave method is used to optimize the geometry structure of Ti doped LiNiO₂, and calculate its crystal structure, atomic layout, density of states, energy band structure and electronic structure. The results show that Ti doped with LiNiO₂ decreases the energy and structure of the system, and makes the ratio of C and c/a increased. The spacing between layers increases, which is favorable for Li⁺ deintercalation and migration, thereby improving its electrochemical performance. Meanwhile, doping Ti affects the arrangement of electrons around O and Ni, making the peripheral O-Ni bond grow, weakening the interaction between O and Ni. O-Ti is close to the O-Ni bond, suppressing the distortion of the eight surface due to Jahn-Teller effect, enhancing the structural stability and improving the cycling performance. Ti doping also decreases the energy of band gap, energy gap and electron transition. At the same time, Li exists in the material in ionic form, which is conducive to the deembedding and diffusion, and enhance the conductivity.