Direct Observation of Defect-Aided Structural Evolution in a Nickel-Rich Layered Cathode.,Angewandte Chemie International Edition

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Direct Observation of Defect-Aided Structural Evolution in a Nickel-Rich Layered Cathode.
Angewandte Chemie International Edition ( IF 16.1 ) Pub Date : 2020-08-02 , DOI: 10.1002/anie.202008144
Shuang Li _{1,

2,

3} , Zhenpeng Yao _{4,

5} , Jianming Zheng _{6,

7} , Maosen Fu ₈ , Jiajie Cen ₉ , Sooyeon Hwang ₃ , Huile Jin ₁ , Alexander Orlov ₉ , Lin Gu ₁₀ , Shun Wang ₁ , Zhongwei Chen ₂ , Dong Su _{3,

10}

Affiliation

Key Laboratory of Carbon Materials of Zhejiang Province, Institute of New Materials and Industrial Technologies, Wenzhou University, Wenzhou, Zhejiang, 325027, China.
Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada.
Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA.
Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA, 02138, USA.
Department of Chemistry and Department of Computer Science, University of Toronto, Toronto, Ontario, M5S 3H6, Canada.
Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA.
College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian, 361005, China.
State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xian, 710072, China.
Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, NY, 11794, USA.
National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.

Ni‐rich LiNi_1−x−yMn_xCo_yO₂ (NMC) layered compounds are the dominant cathode for lithium ion batteries. The role of crystallographic defects on structure evolution and performance degradation during electrochemical cycling is not yet fully understood. Here, we investigated the structural evolution of a Ni‐rich NMC cathode in a solid‐state cell by in situ transmission electron microscopy. Antiphase boundary (APB) and twin boundary (TB) separating layered phases played an important role on phase change. Upon Li depletion, the APB extended across the layered structure, while Li/transition metal (TM) ion mixing in the layered phases was detected to induce the rock‐salt phase formation along the coherent TB. According to DFT calculations, Li/TM mixing and phase transition were aided by the low diffusion barriers of TM ions at planar defects. This work reveals the dynamical scenario of secondary phase evolution, helping unveil the origin of performance fading in Ni‐rich NMC.

中文翻译：

直接观察富含镍的分层阴极中的缺陷辅助结构演变。

富镍LiNi _{1− x − y} Mn _x Co _y O ₂（NMC）层状化合物是锂离子电池的主要阴极。晶体学缺陷在电化学循环过程中对结构演变和性能下降的作用尚不完全清楚。在这里，我们通过原位透射电子显微镜研究了固态电池中富Ni NMC阴极的结构演变。分离相的反相边界（APB）和孪晶边界（TB）在相变中起着重要作用。锂耗尽后，APB延伸穿过层状结构，同时检测到层状相中的Li /过渡金属（TM）离子混合可诱导沿相干TB形成岩盐相。根据DFT计算，在平面缺陷处，TM离子的低扩散势垒有助于Li / TM混合和相变。

更新日期：2020-08-02

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