LAUSR

Nickel‐rich layered oxides are one of the most promising cathode candidates for next‐generation high‐energy‐density lithium‐ion batteries. However, due to similar ion radius between Li+ and Ni2+(0.76 and 0.69 Å), the Li+/Ni2+ mixing phenomenon seriously hinders the migration of Li+ and increases kinetic barrier of Li+ diffusion, resulting in limited rate capability. In this work, the introduction of Ce4+ to effectively improve electrochemical properties of Ni‐rich cathode materials is proposed. The LiNi0.8Co0.15Al0.05O2 (LNCA) is modified with an additional precursor oxidization process using an appropriate amount of (NH4)2Ce(NO3)6. The Ce(NO3)62− easily obtains electrons and generates reduction reactions, while Ni(OH)2 is prone to electron loss and oxidation reaction. The participation of (NH4)2Ce(NO3)6 can promote the oxidation of Ni2+ to Ni3+, thereby reducing the Li+/Ni2+ mixing and increasing the structural stability of LNCA samples. Ce4+ cation doping can impede Li+/Ni2+ mixing of LNCA cathode materials upon the long‐term cycles. Both rate performance and long‐term cyclability of Li[Ni0.8Co0.15Al0.05]0.97Ce0.03O2 (LNCA‐Ce0.03) sample are significantly improved. Besides, a practical pouch cell based on the cathode presents sufficient gravimetric energy density (≈300 Wh kg−1) and cycling stability (capacity retention of 81.3% after 500 cycles at 1 C).