Exploring The Potential and Performance Constraints of Ni-Rich LiNi_0.9Co_0.1O₂ through DFT Research

The high-capacity but unstable LiNiO₂ (LNO) cathode material for lithium-ion batteries can be improved through partial substitution with cobalt. First-principles calculations were performed to study the impact of 10% cobalt doping on the structural, electronic, defect, and lithium diffusion properties of LiNi_0.9Co_0.1O₂ (NC91). The layered structure is retained but the band gap decreases significantly with 10% Co. Formation energies reveal oxygen vacancies and antisite defects still occur; however, Ni sites near Co are least favorable for antisite formation. The energy barrier for Li migration is substantially lower in NC91 than LNO, indicating enhanced Li mobility with 10% Co. While the Co doping improves Li transport, additional doping is likely required to sufficiently suppress cation mixing and oxygen loss. This work provides fundamental insights into the structure-property relationships resulting from low levels of cobalt doping in Ni-rich cathodes.