Ce Modification improves the cycling stability of single-crystal ultra-high nickel cathode materials for lithium-ion batteries

Single-crystal high-nickel cathode materials are among the most promising materials for lithium-ion batteries. However, as the nickel content increases, the degree of cation mixing intensifies, leading to poor cycle performance in ultra-high nickel materials. Here, we used Ce to modify the single-crystal Li[Ni0.92Co0.04Mn0.04]O2 cathode material, alleviating the issue of poor cycle stability in ultra-high nickel materials. Characterization test results demonstrate that the introduction of Ce promotes the growth of single-crystal particles, reduces cation mixing, and mitigates irreversible phase transitions and surface impedance increases during cycling. The Ce-modified single-crystal ultra-high nickel material exhibits excellent cycle stability. After 100 cycles at 1 C in the voltage range of 2.75-4.3 V, the capacity retention of the Ce-modified single-crystal high-nickel material increases from 69.9% to 81.2%. At a high current density of 10 C, the Ce-modified material still retains a high discharge specific capacity of 156.6 mAh g^-1, while the pristine material only reaches 136.8 mAh g^-1.