Molecular O<sub>2</sub> Suppression by Relieving Magnetic Frustration for Sustainable Lithium-Rich Layered Oxides
Xiang Wu, Xiaobing Lou, Yi Liu, Chunjing Hu, Weiran Wang, Jingxin Li, Zhenhua Chen, Haitao Li, Bei Hu, Bei Hu, Chao Li, Bingwen Hu, Bingwen Hu
Abstract
The fundamental barrier to achieving a sustainable anionic redox reaction (ARR) in Li-rich layered oxides stems from the competing requirements of converting lattice oxygen into reversible oxygen dimer while rigorously preventing molecular O 2 formation. Regrettably, this objective remains unattained for application-wise Li-rich layered oxides. We herein reveal that Li 1.2 Ni 0.2 Mn 0.6 O 2 synthesized via conventional carbonate precursors introduces Li[NiMn 5 ] and TM[Ni 2 Mn 4 ] units, significantly exacerbating magnetic frustration and inducing molecular O 2 formation. By contrast, hydroxide-synthesized Li 1.2 Ni 0.2 Mn 0.6 O 2 (H-LNMO) effectively suppresses the formation of Li[NiMn 5 ] and TM[Ni 2 Mn 4 ] while it introduces slight chemical short-range disorder (CSRD), substantially relieving magnetic frustration. This magnetic-frustration-tuning strategy inhibits molecular O 2 formation and oxidizes dimer (O 2 ) n − to higher oxidation states (O 2 ) m − ( m < n ). Resultantly, the capacity retention after 1000 cycles of H-LNMO can elevated from 29.5% to 84.6%, and a first-cycle capacity of 267 mAh/g can be achieved at 0.1C. In addition, this work statistically analyzed other types of layered Li-rich cathodes to prove the universal laws between magnetic frustration and degree of oxygen dimerization, proposing magnetic frustration engineering as an effective strategy to enhance ARR stability in Li-rich layered oxides.