Molecular O₂Suppression by Relieving Magnetic Frustration for Sustainable Lithium-Rich Layered Oxides

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 O₂formation. Regrettably, this objective remains unattained for application-wise Li-rich layered oxides. We herein reveal that Li_1.2Ni_0.2Mn_0.6O₂synthesized via conventional carbonate precursors introduces Li[NiMn₅] and TM[Ni₂Mn₄] units, significantly exacerbating magnetic frustration and inducing molecular O₂formation. By contrast, hydroxide-synthesized Li_1.2Ni_0.2Mn_0.6O₂(H-LNMO) effectively suppresses the formation of Li[NiMn₅] and TM[Ni₂Mn₄] while it introduces slight chemical short-range disorder (CSRD), substantially relieving magnetic frustration. This magnetic-frustration-tuning strategy inhibits molecular O₂formation and oxidizes dimer (O₂)ⁿ⁻to higher oxidation states (O₂)^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.