In this study, the effect of Zn doping on the electrochemical properties of P2-Na 2/3 [Mn 1−x Zn x ]O 2 (x = 0.0, 0.1, 0.2, 0.3) is investigated for the first time. The P2-Na 2/3 [Mn 0.7 Zn 0.3 ]O 2 electrode deliveres a specific discharge capacity of approximately 190 mAh g −1 based on the oxygen-redox reaction (O 2− /O 1− ), after which the Mn 4+ /Mn 3+ redox reaction contributes to the capacity. The cycling performance of the P2-Na 2/3 [Mn 0.7 Zn 0.3 ]O 2 electrode is also greatly enhanced compared with that of the P2-Na 2/3 MnO 2 electrode (capacity retention of 80% vs. 30% after 200 cycles). This improved cyclability is due to the suppression of cooperative Jahn–Teller distortion as well as stabilization of the structure by the electrochemically inactive Zn 2+ ions. First-principle calculations and experimental analysis, including X-ray photoelectron spectroscopy and X-ray absorption near edge structure spectroscopy, clearly confirms that the Zn 2+ substitution in P2-Na 2/3 MnO 2 enables the O 2− /O 1− redox reaction. In addition, time-of-flight secondary ion mass spectroscopy analysis reveals that no sodium carbonates forms on the electrode surface. Our findings provide a potential new path to utilize cost-effective Mn-rich cathode materials for sodium-ion batteries via not only cationic redox but also anodic redox.
- First-principle calculation
- Mn rich
- Sodium ion battery
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)
- Electrical and Electronic Engineering