Oxidation-promoting strategy boosts highly ordered Co-free Ni-rich layered oxides

• Published in: Journal of energy storage 2023-11, Vol.71, p.108021, Article 108021
• Main Authors: Jiang, Sainan, Zhang, Cheng, Zhang, Wujiu, Zhou, Yongjian, Bai, Hengtai, Yuan, Kai, Kou, Liang, Jin, Ting, Tian, Bingbing, Shen, Chao, Xie, Keyu
• Format: Article
• Language: English
• Subjects: Co-free; Li2O2 boosted; Lithium-ion battery; Ni-rich cathode; Pro-oxidization
• ISSN: 2352-152X; 2352-1538
• DOI: 10.1016/j.est.2023.108021

Nickel-rich cobalt-free cathodes are considered as an attractive candidate for next-generation lithium-ion batteries in terms of economic efficiency, environmental friendliness, and energy density. However, high-nickel and zero-cobalt contents are prone to induce layered oxide cathode active materials (CAMs) with undesirable anti-site defects (Li+/Ni2+ mixing) and a defective interface (rock-salt phase layer). Herein, a highly ordered structural LiNi0.80Mn0.17Al0.03O2 CAM was successfully synthesized via the active Li2O2 boosted method. The significant reduction in Li+/Ni2+ mixing (5.5%→2.9%) and thickness of the rock-salt phase interface (5 nm→1.2 nm) vigorously verify the feasibility of this strategy. The evolution of the Ni2+/Ni3+ proportion and primary particle size can further illustrate the co-oxidation mechanism of this strategy. In-situ XRD also shows that the degree of H2-H3 phase transition in the modified sample is relieved, which alleviates the volume change. As a result, the optimized sample displays enhanced cyclability (162.60 mAh/g at 1C over 100 cycles) and advanced rate performance (124.29 mAh/g at 5C). [Display omitted] •Li2O2 with low melting point could provide a liquid phase environment for the sintering and lithiation process of Nickel-rich cathodes.•Strong oxidizing Li2O2 promotes the oxidation from Ni2+ to Ni3+ in LiNi0.80Mn0.17Al0.03O2 with superior electrochemical performance, alleviating Li+/Ni2+ mixing and achieving an ordered layered phase surface.