Iron doping P2-Na2/3Li1/6Fe1/6Mn2/3O2 cathode with enhanced anionic redox and structural stability for sodium-ion batteries
*Correspondence to:
Qingmei Su, Materials Institute of Atomic and Molecular Science, School of Physics & Information Science, Shaanxi University of Science and Technology, Xi’an 710021, Shaanxi, China.
E-mail: suqingmei@sust.edu.cn
Gaohui Du, Materials Institute of Atomic and Molecular Science, School of Physics & Information Science, Shaanxi University of Science and Technology, Xi’an 710021, Shaanxi, China. E-mail: dugaohui@sust.edu.cn
Gaohui Du, Materials Institute of Atomic and Molecular Science, School of Physics & Information Science, Shaanxi University of Science and Technology, Xi’an 710021, Shaanxi, China. E-mail: dugaohui@sust.edu.cn
Smart Mater Devices. 2026;2:202626. 10.70401/smd.2026.0040
Received: May 13, 2026Accepted: July 30, 2026Published: July 30, 2026
This manuscript is made available in its unedited form to allow early access to the
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Abstract
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 (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.
Keywords
Sodium-ion batteries, layered cathode, iron doping, anionic redox, structural stability, Jahn-Teller distortion
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Wang S, Su Q, Wang L, Lai L, Shi W, Shi W, et al. Iron doping P2-Na2/3Li1/6Fe1/6Mn2/3O2 cathode with enhanced anionic redox and structural stability for sodium-ion batteries. Smart Mater Devices. 2026;2:202626. https://doi.org/10.70401/smd.2026.0040
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Wang S, Su Q, Wang L, Lai L, Shi W, Shi W, et al. Iron doping P2-Na2/3Li1/6Fe1/6Mn2/3O2 cathode with enhanced anionic redox and structural stability for sodium-ion batteries. Smart Mater Devices. 2026;2:202626. https://doi.org/10.70401/smd.2026.0040
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