在LiNiO2阴极中的Ni迁移诱导的菌株和相分离
Zhaowen Bai1,2, Subash Kandasamy3, Wei Wang1
1Department of Physics, JC STEM Lab of Energy and Materials Physics, City University of Hong Kong, Hong Kong 999077, China.
ACS nano
|May 15, 2025
概括
在高阴极中的迁移会导致离子电池的结构不稳定性和性能损失. 这项研究揭示了迁移如何导致相位分离和缺陷,影响电池寿命.
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:
- 高层氧化物为下一代离子电池提供高能量密度.
- 高电压下的结构不稳定性限制了这些先进的阴极材料的实际应用.
研究的目的:
- 调查 (Ni) 迁移对相位分离,Li/Ni抗位缺陷和LiNiO (LNO) 机械降解的影响.
- 将原子级格子扭曲与高Ni阴极的长期性能限制联系起来.
主要方法:
- 组合实验技术:同步射线X射线衍射 (XRD),扩展X射线吸收细结构 (EXAFS),传输电子显微镜 (TEM).
- 计算分析:密度函数理论 (DFT) 的计算.
主要成果:
- 在高电压下,Ni迁移到四面体位点,形成具有不同格子行为的共存R3̅m相.
- 阶段分离导致不均的分布,内部应力,应变积累,微裂变和加速降解.
- 连续循环导致不可逆转的Li/Ni抗现场缺陷积累,阻碍离子运输和破坏结构的稳定性.
结论:
- 大量Ni迁移是驱动高Ni阴极相隔离和结构降解的关键因素.
- 了解Ni迁移机制为开发策略提供了见解,比如选择性兴奋剂,以提高结构稳定性和电池性能.
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