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Understanding the Effect of Zn Doping on Stability of Cobalt-Free P2-Na<sub>0.60</sub>Fe<sub>0.5</sub>Mn<sub>0.5</sub>O<sub>2</sub> Cathode for Sodium Ion Batteries
oleh: Devendrasinh Darbar, M. V. Reddy, Indranil Bhattacharya
Format: | Article |
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Diterbitkan: | MDPI AG 2021-06-01 |
Deskripsi
In this work, we report a sol-gel synthesis-based Zn-doped Na<sub>0.6</sub>Fe<sub>0.5</sub>Mn<sub>0.5</sub>O<sub>2</sub> (NFM) cathode and understand the effect of Zn doping on the crystal structure and electrochemical performances such as discharge capacity and rate capability. Detailed X-Ray diffraction (XRD) pattern analysis indicated a decrease in the Na-layer thickness with Zn doping. Small amount of Zn<sup>2+</sup> dopant (i.e., 2 at.%) slightly improved cycling stability, reversibility, and rate performances at higher discharge current rates. For example, at 1 C-rate (1 C = 260 mAh/g), the Zn<sup>2+</sup>-doped cathode retained a stable reversible capacity of 72 mAh/g, which was ~16% greater than that of NFM (62 mAh/g) and showed a minor improvement in the capacity retention of 60% compared to 55% for the pristine NFM after 65 cycles. Slight improvement in the electrochemical performance for the Zn-doped cathode can be attributed to a better structural stability, which prevented the initial phase transition and showed the presence of electrochemical active Fe<sup>3+/4+</sup> even after 10 cycles compared to NFM.