Li Qianqian, Yao Zhenpeng, Lee Eungje, Xu Yaobin, Thackeray Michael M, Wolverton Chris, Dravid Vinayak P, Wu Jinsong
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, Hubei, 430070, China.
Materials Genome Institute, Shanghai University, Shanghai, 200444, China.
Nat Commun. 2019 Apr 12;10(1):1692. doi: 10.1038/s41467-019-09408-2.
Crystalline defects are commonly generated in lithium-metal-oxide electrodes during cycling of lithium-ion batteries. Their role in electrochemical reactions is not yet fully understood because, until recently, there has not been an effective operando technique to image dynamic processes at the atomic level. In this study, two types of defects were monitored dynamically during delithiation and concomitant oxidation of oxygen ions by using in situ high-resolution transmission electron microscopy supported by density functional theory calculations. One stacking fault with a fault vector b/6[110] and low mobility contributes minimally to oxygen release from the structure. In contrast, dissociated dislocations with Burgers vector of c/2[001] have high gliding and transverse mobility; they lead to the formation, transport and release subsequently of oxygen related species at the surface of the electrode particles. This work advances the scientific understanding of how oxygen participates and the structural response during the activation process at high potentials.
在锂离子电池循环过程中，锂金属氧化物电极中通常会产生晶体缺陷。它们在电化学反应中的作用尚未完全明确，因为直到最近，还没有一种有效的原位技术能够在原子水平上对动态过程进行成像。在本研究中，通过使用密度泛函理论计算支持的原位高分辨率透射电子显微镜，在脱锂和氧离子伴随氧化过程中对两种类型的缺陷进行了动态监测。一种位错矢量为b/6[110]且迁移率低的堆垛层错对结构中氧的释放贡献极小。相比之下，柏氏矢量为c/2[001]的解离位错具有高滑移和横向迁移率；它们导致电极颗粒表面氧相关物种的形成、传输和随后的释放。这项工作推进了对氧在高电位激活过程中如何参与以及结构响应的科学理解。
