Atomistic understanding of capacity loss in LiNiO₂ for high-nickel Li–ion batteries: First-principles study

Abstract

Combining the first-principles calculations and structural enumeration with recognition, we have investigated the delithiation process of LiNiO2, where various supercell shapes have been considered to obtain the formation energy of Li x NiO2.Meanwhile, we simulate the voltage profile and predict the ordered phases of lithium vacancies corresponding to concentrations of 1/4, 2/5, 3/7, 1/2, 2/3, 3/4, 5/6, and 6/7. To understand the capacity decay in the experiment during the charge/discharge cycles, we have performed the calculations for deoxygenation and Li/Ni antisite defects, revealing that the chains of oxygen vacancies will be energetically preferrable. It can be inferred that with the absence of oxygen atom in high delithiate state, the diffusion of Ni atoms will be facilitated and induce the formation of Li/Ni antisite.