1. High-performance P2-Type Fe/Mn-based oxide cathode materials for sodium-ion batteries.
- Author
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Tang, Ke, Wang, Yu, Zhang, Xiaohui, Jamil, Sidra, Huang, Yan, Cao, Shuang, Xie, Xin, Bai, Yansong, Wang, Xianyou, Luo, Zhigao, and Chen, Gairong
- Subjects
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FERRIC oxide , *VALENCE fluctuations , *CATHODES , *ELECTRIC batteries , *TRANSITION metals , *MICROSPHERES - Abstract
P2-type Fe/Mn-based oxides are considered as the competitive cathode materials for sodium-ion batteries because of high specific capacity and low material cost. However, it suffers from poor cycling stability and unsatisfactory rate capability. Herein, the lithium-doped Na 0.67 Li 0.1 Fe 0.4 Mn 0.5 O 2 microspheres are successfully synthesized via a three-step method. Benefiting from the synergetic effect of the double modification through the morphology controlling and lithium doping, the Na 0.67 Li 0.1 Fe 0.4 Mn 0.5 O 2 delivers an improved cycling stability and rate performance. Moreover, fluorine is successfully introduced to further improve the electrochemical performance of the Na 0.67 Li 0.1 Fe 0.4 Mn 0.5 O 2. Fluorine doping can boost the stability of the material crystal structure because of the strong electronegativity of fluorine and the stable fluorine-metal bond. Meanwhile, fluorine doping avoids the formation of extra O3 phase by reducing the average valence of transition metals. Most importantly, P2-type 10 mol% F-Na 0.67 Li 0.1 Fe 0.4 Mn 0.5 O 2 shows a high discharge specific capacity of 182.0 mAh g-1 at 20 mA g-1, excellent capacity retention of 90.0% after 50 cycles and outstanding rate performance of 128.7 mAh g−1 at 400 mA g-1. Apparently, such a modification strategy apparently promotes the electrochemical performances of the P2-type Fe/Mn-based oxide and increases the commercial application possibilities of this cathode material in sodium-ion batteries. • P2/O3-type Li-doped NLFMO microspheres are successfully synthesized. • NLFMO microspheres delivers improved cycling stability and rate performance. • Pure P2-type NLFMO microspheres are synthesized by 10 mol% fluorine doping. • P2-type 10 mol% F-NLFMO displays higher specific capacity than NLFMO. • P2-type 10 mol% F-NLFMO also shows better cyclic stability and rate capability. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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