Unraveling the composition-structure interplay in Ultrahigh-Ni precursors toward precision cathode performance engineering

Ultrahigh-nickel (UHN, Ni ≥ 0.9) cathodes have attracted significant interest due to the high energy density and reduced cobalt dependency. However, residual lithium compounds on the surface severely impede Li⁺ migration and trigger adverse side reactions. Herein synergistic strategy involving the regulation of precursor primary particle morphology and the doping of W and Nb, achieving dual optimization of the bulk structure and interfacial stability. The incorporation of Nb and W promotes preferential growth of primary particles along the {010} facets, exposing more Li⁺diffusion pathways. Moreover, the high valence states and large ionic radii induce strong electrostatic repulsion, effectively expanding the c -axis spacing and increasing the Li⁺ diffusion coefficient. Results demonstrate that the Li⁺ diffusion coefficients of Nb-doped (4.82 × 10^–8 cm²·s^-1) and W-doped (1.07 × 10^–7 cm²·s^-1) significantly exceed that of the undoped N93 (3.74 × 10^–8 cm²·s^-1). Besides, optimize the aspect ratio of grains effectively reduces surface lithium residues and enhance cycling stability. The N93-Nb retains 74.31% of its capacity after 300 cycles at 1 C, significantly outperforming comparative samples. Further mechanistic studies reveal that the structure-performance regulation mechanism mediated by dopants, providing both theoretical insights and a practical pathway for the industrial application of UHN cathodes.