In Situ Probing and Synthetic Control of Cationic Ordering in Ni‐Rich Layered Oxide Cathodes |
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| Authors: | Jianqing Zhao Wei Zhang Ashfia Huq Scott T. Misture Boliang Zhang Shengmin Guo Lijun Wu Yimei Zhu Zonghai Chen Khalil Amine Feng Pan Jianming Bai Feng Wang |
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| Affiliation: | 1. Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, NY, USA;2. School of Energy, College of Physics, Optoelectronics & Energy, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, P. R. China;3. Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA;4. Kazuo Inamori School of Engineering, Alfred University, Alfred, NY, USA;5. Department of Mechanical & Industrial Engineering, Louisiana State University, Baton Rouge, LA, USA;6. Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY, USA;7. Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL, USA;8. School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen, Guangdong, P. R. China;9. National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA |
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| Abstract: | Ni‐rich layered oxides (LiNi1–x Mx O2; M = Co, Mn, …) are appealing alternatives to conventional LiCoO2 as cathodes in Li‐ion batteries for automobile and other large‐scale applications due to their high theoretical capacity and low cost. However, preparing stoichiometric LiNi1–x Mx O2 with ordered layer structure and high reversible capacity, has proven difficult due to cation mixing in octahedral sites. Herein, in situ studies of synthesis reactions and the associated structural ordering in preparing LiNiO2 and the Co‐substituted variant, LiNi0.8Co0.2O2, are made, to gain insights into synthetic control of the structure and electrochemical properties of Ni‐rich layered oxides. Results from this study indicate a direct transformation of the intermediate from the rock salt structure into hexagonal phase, and during the process, Co substitution facilities the nucleation of a Co‐rich layered phase at low temperatures and subsequent growth and stabilization of solid solution Li(Ni, Co)O2 upon further heat treatment. Optimal conditions are identified from the in situ studies and utilized to obtain stoichiometric LiNi0.8Co0.2O2 that exhibits high capacity (up to 200 mA h g?1 ) with excellent retention. The findings shed light on designing high performance Ni‐rich layered oxide cathodes through synthetic control of the structural ordering in the materials. |
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| Keywords: | lithium ion batteries Ni‐rich layered oxide cathodes cationic ordering in situ XRD |
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