积极电极材料中的短距离和长距离顺序,Li ((NiMn) 0.5O2:联合X射线和中子衍射,对分布函数分析和NMR研究研究
Julien Bréger1, Nicolas Dupré, Peter J Chupas
1Department of Chemistry, State University of New York at Stony Brook, 11794, USA.
Journal of the American Chemical Society
|May 19, 2005
概括
这项研究揭示了离子电池的LiNi{0.5}Mn{0.5}O{2}) 阴极材料的短距离排序. 先进的分析显示过渡金属的非随机分布,影响电池性能.
科学领域:
- 材料科学 材料科学 材料科学
- 固态化学 固态化学
- 电化学 电化学 电化学
背景情况:
- -氧化 (LiNi{0.5}Mn{0.5}O{2}) 是离子电池的一个有前途的阴极材料.
- 了解当地环境和短距离订购对于优化其电化学性能至关重要.
研究的目的:
- 为了研究当地的原子环境和LiNi{0.5}Mn{0.5}O{2}中的短距离离子排序.
- 为了阐明Li,Ni和Mn离子在过渡金属层中的分布.
主要方法:
- 结合X射线和中子衍射,包括同位素替代 (NDIS).
- (6) 神奇角度旋转 (MAS) 核磁共振 (NMR) 光谱学.
- 在X射线和中子对分布函数 (PDF) 分析与逆蒙特卡洛 (RMC) 建模相结合.
主要成果:
- 在和过渡金属层之间观察到约10%的Ni/Li位点交换.
- PDF分析显示了局部扭曲和明显的M-O债券长度 (Mn-O:1.93 Å,Ni/Li-O:2.07 Å).
- 核磁共振和核磁共振结果表明,的分布非随机,Ni和Li原子偏好位于Mn离子附近,这表明短距离的顺序.
结论:
- 过渡金属层表现出短距离的顺序,形成像LiMn6和LiMn5这样的集群.
- 阴子分布偏离随机性,类似于从有序的蜂数组中得出的结构.
- 这些发现为LiNi{0.5}Mn{0.5}O2的局部结构提供了关键的见解,这对于设计先进的离子电池阴极至关重要.
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