Inhibiting Oxygen Vacancies via Mo Doping to Enhance the Cycle Stability of Ni-Rich Single-Crystal Cathodes

Ni-rich single-crystal cathode materials have garnered significant attention for their ability to minimize intergranular cracking, enhancing cycling stability compared with polycrystalline counterparts. However, they remain susceptible to structural degradation, such as interlayer mixing, irreversible phase transformation, and intragranular cracking, which compromise the capacity during extended cycling. This study presents a strategy to address these defects by incorporating Mo through a two-step sintering process. Mo doping effectively suppresses the formation of oxygen vacancies, which is critical to the intragranular cracking formation, thereby improving structural stability and mechanical integrity. As a result, the doped cathodes demonstrate superior electrochemical performance, reduced impedance growth, and an enhanced cycle life. These findings offer valuable insights into the role of high-valence dopants in stabilizing single-crystal cathodes and contribute to developing high-performance lithium-ion batteries for next-generation applications.