Oxygen loss mitigation and structural stability via synergistic Zr/F dual-doping in O3 type Ni/Mn based layered oxide for sustainable sodium-ion batteries cathodes

O3-type Ni/Mn-based transition metal oxides have garnered significant interest as cathode materials for sodium-ion batteries (SIBs) due to their high specific capacity and abundant resources. However, their commercialization application has been impeded by rapid capacity fading owing to structural degradation, gas evolution, irreversible phase transitions during charge/discharge cycling. Herein, The Zr 4 + /F - dual-doped strategy is developed to boost the Na-storage performance of Ni/Mn-based O3-NaNi 0.3 Fe 0.1 Mn 0.47 Cu 0.1 Zr 0.03 O 2-x F x (NFMCZF-x) layered oxide cathode material prepared by high temperature calcination method. Structural and electrochemical analyses reveal that Zr⁴⁺ doping expands Na⁺-layer spacing and F⁻ doping strengthens transition metal-oxygen bonds. These synergistic effects of Zr 4+ /F - dual-doping is benefit to suppressing O3↔P3 phase transitions, Jahn-Teller distortion and irreversible oxygen redox. Thus, the optimized NFMCZF-0.03 cathode delivers high specific capacity (178 mAh g −1 at 0.1 C) and excellent cycling stability (72 % capacity retention after 100 cycles at 1.0 C). This study establishes dual doping as an effective strategy for developing Ni/Mn-based layered oxide as high-performance cathodes for SIBs.