Design and tailoring of carbon-Al2O3 double coated nickel-based cation-disordered cathodes towards high-performance Li-ion batteries

Li-excess cation-disordered oxide cathodes have attracted increasing interests owing to their high energy density originated from cumulative cationic & anionic redox activity. In particular, Ni-based cation-disordered oxides exhibit high theoretical capacity for 2 e(-) reactions of Ni2+/Ni4+ , while the severe overlapping between Ni 3d and O 2p orbitals restricts Ni redox capacity and unstable O redox deteriorates the cycling performance. Benefiting from advanced data mining and high-throughput theoretical calculations technology, we demonstrated that the capacity and cycling performance of Ni-based cation-disordered oxide can be synergically enhanced by carbon/Al2O3 double coating and partial Al3+ substitution. The synergistic mechanism is unveiled via X-ray photoelectron spectroscopy (XPS) and soft X-ray absorption spectroscopy (XAS) characterization together with first-principles calculations. It is confirmed that carbon coating increases the capacity by promoting the formation of peroxo-like species, which boosts O redox activity. Partial intercalating Al3+ enhances the Ni redox reaction by shortening the band overlap between Ni and O. Furthermore, Al2O3 coating and Al3+ doping improved the cycling stability of the cathode material owing to the shielding effect on side reaction and more stable O lattice. This synergistic strategy with nano-coating layer provides a promising pathway to accelerate the discovery of high-energy cation-disordered oxides based cathode materials.

Automated summary

Li-excess cation-disordered oxide cathodes with high energy density have attracted attention. In this study, it was found that carbon/Al2O3 double coating and partial Al3+ substitution can enhance the capacity and cycling performance of Ni-based cation-disordered oxide cathodes. Carbon coating promotes O redox activity, while Al3+ substitution shortens the band overlap between Ni and O. Additionally, Al2O3 coating and Al3+ doping improve the cycling stability of the cathode material.