Study on d0 transition metals doped Ni-rich cathode materials for Li-ion batteries: Insights from first-principles calculations

Ni-rich layered oxides are promising cathode materials for next generation Li-ion batteries due to high energy density. However, structural instability severely constrains its application during charging/discharging. Herein, we performed first-principles calculations to study the mechanism of performance improvement by d0 transition metal doping. The results show that the d0 cation Ti4+, V5+ and Mo6+ doping is beneficial to suppress the lattice distortion of the Ni-rich cathode during delithiation process, especially in the c-direction. Moreover, d0 cation doping can deliver high intercalation potentials, thereby increasing the energy density of the Li-ion batteries. Among them, Mo6+ is considered as the most ideal dopant in improving the structural stability and energy density. However, it is disappointing that d0 cation doping accelerates the formation of O-vacancies in Ni-rich cathode materials. These theoretical findings provide a new insight for the doping strategy of Ni-rich cathode materials, which is helpful for designing high performance cathodes.