Redox from the holes at the O2p orbitals is a well‐known phenomenon in Li‐rich Mn‐based batteries. However, such an anionic redox process results in the formation of O2, leading to structural instability owing to unstable O2p holes. Herein, a swing‐like non‐isothermal sintering technique is used to stabilize the lattice oxygen by suppressing the formation of O2 during charging. It reduces both the number of intrinsic oxygen vacancies of the Li‐rich Mn‐based oxides and the formation of O2 during charging as compared with traditional constant high‐temperature sintering. Consequently, the number of holes generated during charging in the O2p orbitals increases, whereas the number of unstable O2p holes forming O2 decreases. Therefore, the sample prepared via swing‐like non‐isothermal sintering exhibited considerably slower voltage fading and better cycling stability. This study provides valuable guidelines for stabilizing the lattice oxygen and improving the structural stability of the oxide cathodes for electrochemical energy storage.

Most layered oxide cathode materials for sodium-ion batteries (SIBs) bear large structural irreversibility upon electrode reaction, and the rod-like Na0.44MnO2 (NMO) has shown its specific merit on the structural integrity...

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O3-type Fe/Mn-based layered oxide cathode materials with abundant reserves have a promising prospect in sodium-ion batteries. However, the electrochemical reversibility of most O3-type Fe/Mn-based oxide cathode materials is still not high enough. Herein, the effect of different Cu contents on the electrochemical properties of O3-NaFe 0.50 Mn 0.50 O 2 materials is systematically investigated. The as-prepared NaFe 0.30 Mn 0.50 Cu 0.20 O 2 cathode achieves the synergistic optimization of the interface and bulk phase. It shows superior electrochemical performance, with an initial discharge specific capacity of 114 mAh g À 1 at 0.1 C, a capacity retention rate of 94 % after 100 cycles at 0.5 C, and excellent chemical stability in air and water. In addition, the sodium ion full battery based on NaFe 0.30 Mn 0.50 Cu 0.20 O 2 cathode and hard carbon anode has a capacity retention rate of 81 % after 100 cycles. This research provides a useful approach for the preparation of low-cost and high-performance O3-type layered cathode materials.