纳米结构转化作为丰富3d和4d阴极中的氧化还氧化特征
Antonin Grenier1, Gabrielle E Kamm1, Yixuan Li2
1Department of Chemistry, Stony Brook University, 100 Nicolls Road, Stony Brook, New York 11794, United States.
Journal of the American Chemical Society
|April 7, 2021
概括
富氧化物 (LRNMC) 阴极在氧化过程中形成纳米孔,影响性能. 了解这种结构变化是提高电池循环稳定的关键.
科学领域:
- 材料科学
- 电化学
- 固态化学
背景情况:
- 富氧化 (LRNMC) 的能量密度高于传统的NMC和NCA阴极材料.
- LRNMC的高容量与可逆氧 (O) 反氧化化学有关.
- 在LRNMC中适应O氧还原变化的结构机制尚不清楚,阻碍了性能优化.
研究的目的:
- 研究LRNMC阴极材料中氧化的结构后果.
- 在循环过程中阐明纳米尺度结构变化的形成和可逆性.
- 将这些变化与传统的阴极材料进行比较.
主要方法:
- 小角度X射线散射 (SAXS) 来检测纳米级结构特征.
- 在电化学循环过程中使用X射线衍射 (XRD) 监测结构演变.
- 对LRNMC,Li2RuO3和Li1.3Nb0.3Mn0.4O2系统进行分析.
主要成果:
- 在LRNMC中确定了较低电子密度的纳米级域,与O氧化相关.
- 在氧化过程中观察到表明纳米孔形成的散射特征,显示部分可逆性.
- 这种纳米孔特征在石化NMC和NCA中不存在,但在其他富含的材料中存在.
结论:
- 在LRNMC中氧化导致纳米级域和纳米孔的形成.
- 这些结构变化对于理解容量衰减和设计稳定的LRNMC阴极至关重要.
- 观察到的纳米性是丰富的正极材料的特征.
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