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

• Published in: Nano energy 2022-06, Vol.96, p.107071, Article 107071
• Main Authors: Yu, Zhenlu, Huang, He, Liu, Yunjian, Qu, Xingyu, Zhou, Yu, Dou, Aichun, Su, Mingru, Wu, Hong-Hui, Zhang, Liang, Dai, Kehua, Guo, Zaiping, Wan, Tao, Li, Mengyao, Chu, Dewei
• Format: Article
• Language: English
• Subjects: Anionic redox; Cation-disordered cathode; Cycling performance; Double coating; Li-ion batteries
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2022.107071

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. [Display omitted] •A novel coating strategy to improve cation-disordered cathode performance is proposed.•Cation-disordered cathode with enhanced capacity and cycling performance is achieved.•Carbon/Al2O3 double coating and Al3+ doping improve the redox activities of Ni and O.•O2 release upon cycling is inhibited in the carbon/Al2O3 double-coated sample.