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Bimetal Substitution Enabled Energetic Polyanion Cathode for Sodium-Ion Batteries
Nano Letters ( IF 9.6 ) Pub Date : 2022-11-28 , DOI: 10.1021/acs.nanolett.2c03916
Qing-Yuan Zhao 1 , Jiang-Yu Li 1 , Meng-Jie Chen 1 , Hongrui Wang 1 , Yu-Ting Xu 2 , Xiao-Feng Wang 2 , Xin Ma 3 , Qing Wu 4 , Xiongwei Wu 1 , Xian-Xiang Zeng 1
Affiliation  

The practical application of Na-superionic conductor structured materials is hindered by limited energy density and structure damage upon activating the third Na+. We propose a bimetal substitution strategy with cheaper Fe and Ni elements for costive vanadium in the polyanion to improve both ionic and electronic conductivities, and a single two-phase reaction during Na+ intercalation/deintercalation and much reduced Na+ diffusion barrier are uncovered by ex-situ X-ray diffraction and density functional theory calculations. Thus, the obtained cathode, Na3Fe0.8VNi0.2(PO4)3, shows excellent electrochemical performances including high specific capacity (102.2 mAh g–1 at 0.1C), excellent rate capability (79.3 mAh g–1 at 20C), cycling stability (84.6% of capacity retention over 1400 cycles at 20C), low-temperature performance (89.7 mAh g–1 at 2C and −10 °C), and structure stability in an extended voltage window for the third Na+ utilization. A competitive energy density of ≈287 Wh kg–1 for full batteries based on cathode and anode materials is also confirmed.

中文翻译:

用于钠离子电池的双金属替代启用高能聚阴离子阴极

Na-超离子导体结构材料的实际应用受到有限的能量密度和激活第三个 Na +时结构损伤的阻碍。我们提出了一种双金属替代策略,用更便宜的 Fe 和 Ni 元素替代聚阴离子中的成本钒,以提高离子和电子电导率,并且 ex 发现了 Na +嵌入/脱嵌过程中的单一两相反应和大大降低的 Na +扩散势垒-原位X射线衍射和密度泛函理论计算。由此,得到正极,Na 3 Fe 0.8 VNi 0.2 (PO 4 ) 3, 显示出优异的电化学性能,包括高比容量(102.2 mAh g –1在 0.1C)、出色的倍率性能(79.3 mAh g –1在 20C)、循环稳定性(84.6% 的容量保持率在 20C 下超过 1400 个循环)、低-温度性能(2C 和 −10 °C 时为 89.7 mAh g –1 ),以及第三次 Na +利用的扩展电压窗口中的结构稳定性。基于阴极和阳极材料的全电池的竞争性能量密度≈287 Wh kg –1也得到证实。
更新日期:2022-11-28
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