Scalable shell doping strategy for enhancing the stability of Ni-rich cathode materials

Abstract

To improve the stability of Ni-rich Li[Ni_0.90Co_0.05Mn_0.05]O₂ (NCM90) cathodes, doping has proven to be an effective method for enhancing the performance of cathode materials. Nevertheless, the dry-doping process, which involves the mixing of the cathode precursor with lithium sources and dopants, is constrained by limitations in scalability and efficacy. This study introduces a wet-doping approach that focuses on the shell region (shell doping) with the objective of maximizing the doping effect and offering benefits in scaling up the cathode material production process in terms of commercialization. The W-shell doped NCM90 cathodes, prepared by doping W in the shell region of the secondary particle during the co-precipitation synthesis process of the [Ni_0.90Co_0.05Mn_0.05](OH)₂ precursor, exhibit the formation of fine primary particles that are not observed in conventional NCM90 cathodes. Additionally, it forms a LiM₂O₄-type spinel-like crystal structure on the particle surface, contributing to improved cycling stability and rate capability. Furthermore, the shell doping method, which facilitates the uniform distribution of dopants throughout the co-precipitation synthesis process, was capable of maintaining the homogeneity of the doping effect even in large-scale cathode material synthesis processes. These findings extend beyond the discovery of a new doping method for enhancing cathode performance, offering a practical approach that can be applied to large-scale production processes from a commercialization perspective.