在丰富的层状氧化物中结构降解之间的相对应速度依赖的过渡金属溶解
Bo Cao1, Tianyi Li2, Wenguang Zhao1
1School of Advanced Materials, Peking University, Shenzhen Graduate School, Shenzhen, 518055, People's Republic of China.
Small (Weinheim an der Bergstrasse, Germany)
|June 21, 2023
概括
研究离子电池阴极揭示了不同的降解机制. 低速循环会导致散装结构损坏,而高速循环会导致表面退化,这两者都会影响电池性能.
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
- 电池技术 电池技术
背景情况:
- 开发用于离子电池 (LIB) 的先进阴极对于快速充电应用至关重要.
- 了解不同循环速率下的性能退化机制对于LIB改进至关重要.
研究的目的:
- 为了研究丰富的多层氧化物阴极中的取决于速率的降解机制.
- 为了比较低和高循环速率的性能退化,重点关注过渡金属溶解和结构变化.
主要方法:
- 使用空间分辨率的同步龙X射线光 (XRF) 成像.
- 使用同步射线X射线衍射 (XRD) 和传输电子显微镜 (TEM) 进行定量分析.
- 分析了Li1.2Ni0.13Co0.13Mn0.54O2作为一个模型阴极材料.
主要成果:
- 低速循环诱导梯度过渡金属 (TM) 溶解和大量结构降解,导致微裂和容量衰减.
- 高速循环导致了更多的TM溶解,聚焦在粒子表面,导致表面结构严重退化到不活跃的岩盐阶段.
- 这两种机制都导致容量和电压下降,高速循环显示出由于表面效应而导致的更快下降.
结论:
- 表面结构的保护对于开发高性能,快速充电的阴极至关重要.
- 在低速和高速的不同降解路径需要为正极材料设计和优化量身定制的策略.
- 了解这些机制是提高离子电池循环寿命和速率能力的关键.
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