在电池阴极中证明了氧气损失和相关的结构重组Li[Ni0.2Li0.2Mn0.6]O2O2
A Robert Armstrong1, Michael Holzapfel, Petr Novák
1EaStCHEM, School of Chemistry, University of St Andrews, St. Andrews, Fife, KY16 9ST, United Kingdom.
Journal of the American Chemical Society
|June 29, 2006
概括
这项研究表明,在充电过程中,氧气 (O2) 从---氧化阴极释放出来. 这种非传统的提取机制提高了先进的离子电池的充电储能.
科学领域:
- 材料科学 材料科学 材料科学
- 电化学 电化学 电化学
- 固态化学 固态化学
背景情况:
- 传统的离子电池阴极,如LiCoO2,依赖于间隙和Co-ion氧化还原来储存电荷.
- -Mn-Ni-O化合物具有更高能量密度的潜力,但涉及非传统的提取机制.
- 了解这些机制对于开发下一代高性能电池至关重要.
研究的目的:
- 阐明从基于Mn4+的阴极材料中提取的机制,特别是Li[Ni[0.2) Li[0.2) Mn[0.6) ]O2.
- 研究充电过程中氧气进化的作用.
- 为了将观察到的机制与增强的电荷存储能力相关联.
主要方法:
- 在现场微分电化学质谱 (DEMS) 检测进化气体.
- 粉末中子衍射分析结构变化.
- 电化学循环,以评估电荷存储性能.
主要成果:
- 在充电过程中,有直接证据表明氧气 (O2) 从Li[Ni{0.2}Li{0.2}Mn{0.6}]O2中演变.
- 观察从表面到散装的过渡金属离子扩散,占用空缺.
- 结构转变向MO2组成.
- 与LiCoO2 (140 mAhg-1) 相比,显示了显著更高的电荷存储容量 (200 mAhg-1).
结论:
- 从Li-Mn-Ni-O阴极中提取通过一种非常规的途径进行,涉及同时去除和氧气.
- 氧的演变和随后的过渡金属迁移是实现高电荷密度的关键.
- 这种理解有助于设计用于高能离子电池的先进阴极材料.
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