Iron doping P2-Na2/3Li1/6Fe1/6Mn2/3O2 cathode with enhanced anionic redox and structural stability for sodium-ion batteries
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P2-type layered manganese-based oxides are promising cathode materials for sodium-ion batteries (SIBs) but suffer from structural instability and irreversible phase transitions. This study demonstrates that iron doping in P2-Na2/3Li1/6Fe1/6Mn2/3O2 ...
MoreP2-type layered manganese-based oxides are promising cathode materials for sodium-ion batteries (SIBs) but suffer from structural instability and irreversible phase transitions. This study demonstrates that iron doping in P2-Na2/3Li1/6Fe1/6Mn2/3O2 (NLFM) effectively reconfigures the structural and redox chemistry. Structural and electrochemical analyses reveal that Fe3+ incorporation expands the Na+ interlayer spacing, enhances reversible cationic (Fe3+/Fe4+) and anionic redox activity, and promotes a dominant surface-controlled charge storage mechanism. Consequently, the NLFM cathode delivers a high initial capacity of 225 mAh·g-1 at 0.1 C, an impressive initial Coulombic efficiency of 110.21%, and superior cycling stability (73.6% capacity retention after 100 cycles at 1 C). Furthermore, Fe doping effectively mitigates the Jahn-Teller distortion and mitigates the reversible P2 to O2 phase transition at high voltages. This work highlights the multi-functional role of iron doping in stabilizing the structure and optimizing the redox chemistry of P2-type cathodes, providing an effective strategy for developing high-energy and durable SIBs cathodes.
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Siyu Wang, ... Gaohui Du
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DOI: https://doi.org/10.70401/smd.2026.0040 - July 30, 2026






