Site selectivity of single dopant in high-nickel cathodes for lithium-ion batteries

Improving the structural stability of high-capacity high-Ni cathodes through doping has been investigated, but the structural stabilization mechanisms of dopants remain unclear. This study focused on unraveling the influence of individual dopants, Aluminium, Titanium, or Zirconium, on the structural stabilization of high-Ni cathodes. X-ray Diffraction and High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy (HAADF-STEM) were employed for quantitative analysis of cation mixing, and for the first time, HAADF-STEM and deep learning were combined to improve the accuracy and efficiency of the analysis. The atomic-scale energy dispersive spectroscopy analysis identified transition metal sites as the primary doping sites in doped high-Ni cathodes. Density funtional theory calculations revealed that dopants enhance the interatomic bonds between Ni and O, thereby inhibiting cation mixing. Among the studied dopants, Ti was found to have the most substantial influence in enhancing structural stability. This study contributes to an understanding of single dopant on the structural stability of high-Ni cathodes, aiding the design of next-generation lithium-ion batteries.