阳离子聚合
替代(逻辑)
锰
材料科学
氧化锰
对偶(语法数字)
钠
氧化物
无机化学
替代效应
氧化钠
化学工程
冶金
高分子化学
化学
艺术
文学类
新古典经济学
计算机科学
经济
工程类
程序设计语言
作者
Hyung-Seok Kim,Natalia Voronina,Konstantin Köster,A. E. Kim,Hun‐Gi Jung,Hyungsub Kim,Koji Yazawa,Hitoshi Yashiro,Payam Kaghazchi,Seung‐Taek Myung
标识
DOI:10.1016/j.ensm.2024.103224
摘要
P2-type sodium-deficient cathodes with the local Na–O–A configuration (A=Li, Mg, Zn, and vacancy) have attracted great interest due to their high capacity, stemming from the additional contribution of the oxygen-redox chemistry. However, such materials suffer from irreversible oxygen redox, oxygen release, structural distortion, and capacity fading. Herein, we introduce a dual-doping Li/Cu strategy to improve the properties of P2-NaxMnO2 cathode material. The unique sodium-storage mechanism in P2-Na0.75[Li0.15Cu0.15Mn0.7]O2 is verified using operando X-ray diffraction (o-XRD), X-ray absorption, X-ray photoelectron spectroscopy, and magnetic susceptibility methods. O-XRD and 7Li solid-state nuclear magnetic resonance analysis reveal that the P2 phase is maintained within charge and discharge; however, at high voltage, a small portion of O-type stacking faults are emerged due to the migration of Li to octahedral Na sites. Furthermore, various spectroscopy and magnetometry techniques combined with density functional theory calculation demonstrate the stable activity of cationic Cu2+/Cu3+ and Mn3+/Mn4+ and anionic O2−/(O2)n− redox processes. This work highlights the efficacy of Li and Cu doping in P2-type layered materials and the contribution of oxygen redox to additional capacity at high voltages, suggesting the potential for future development of cathode materials for Na-ion batteries with oxygen redox.
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