Realizing high initial Coulombic efficiency in manganese-based layered oxide cathodes for sodium-ion batteries via P2/O′3 biphasic structure optimization.
In: Rare Metals, Jg. 43 (2024-05-01), Heft 5, S. 2093-2102
Online
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Zugriff:
Mn-based layered oxides are among the most promising cathode materials for sodium-ion batteries owing to the advantages of abundance, environmental friendliness, low cost and high specific capacity. P2 and O′3 are two representative structures of Mn-based layered oxides. However, the P2 structure containing insufficient Na generally exhibits low initial charge capacity, while O′3 structure with sufficient Na delivers high initial charge capacity but poor cycle stability. This study prepared a multitude of Na x MnO 2 (x = 0.7, 0.8, 0.9) cathode materials with varying P2/O′3 ratios and further investigated their electrochemical performances. The optimized Na 0.8 MnO 2 , comprising 69.9 wt% O′3 and 30.1 wt% P2 phase, exhibited relatively balanced specific capacity, Coulombic efficiency and cycle stability. Specifically, it achieved a high specific capacity of 128.9 mAh·g −1 with an initial Coulombic efficiency of 98.2% in half-cell configuration. The Na 0.8 MnO 2 //hard carbon full cell also achieved a high specific capacity of 126.7 mAh·g −1 with an initial Coulombic efficiency of 98.9%. Moreover, the capacity fading mechanism was revealed by combining in-situ and ex-situ X-ray diffraction. The findings of this study provide theoretical guidance for further modification design of Mn-based layered cathodes. [ABSTRACT FROM AUTHOR]
摘要: 锰基层状氧化物具有资源丰富、环保、低成本、高比容量等优点, 是钠离子电池中极具发展前景的正极材料之一。P2和O′3相是锰基层状氧化物中的两种代表性结构。然而, 含Na不足的P2相结构通常具有较低的初始充电容量, 而含有足量Na的O′3相结构虽具有较高的初始充电容量, 但其循环稳定性较差。本研究工作制备了多种不同P2/O′3比例的Na x MnO 2 (x = 0.7, 0.8, 0.9) 正极材料, 并进一步研究其电化学性能。优化的Na 0.8 MnO 2 正极材料 (其中O′3相含量为69.9 wt%, P2相含量为30.1 wt%) 具有相对平衡的比容量、库仑效率和循环稳定性。具体来说, 它在半电池配置下实现了128.9 mAh·g −1 的高比容量和98.2%的初始库仑效率。Na 0.8 MnO 2 //硬碳全电池可实现126.7 mAh·g −1 的高比容量, 初始库仑效率达到了98.9%。此外, 通过结合原位和非原位X射线衍射, 揭示了容量衰退机制。研究结果为锰基层状正极的进一步改性设计提供了理论指导。 [ABSTRACT FROM AUTHOR]
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Titel: |
Realizing high initial Coulombic efficiency in manganese-based layered oxide cathodes for sodium-ion batteries via P2/O′3 biphasic structure optimization.
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Autor/in / Beteiligte Person: | Peng, Bo ; Zhou, Zi-Hao ; Xuan, Ping ; Xu, Jie ; Ma, Lian-Bo |
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Zeitschrift: | Rare Metals, Jg. 43 (2024-05-01), Heft 5, S. 2093-2102 |
Veröffentlichung: | 2024 |
Medientyp: | academicJournal |
ISSN: | 1001-0521 (print) |
DOI: | 10.1007/s12598-023-02581-w |
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