A Novel Cathode Material with a Concentration‐Gradient for High‐Energy and Safe Lithium‐Ion Batteries |
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| Authors: | Yang‐Kook Sun Dong‐Hui Kim Chong Seung Yoon Seung‐Taek Myung Jai Prakash Khalil Amine |
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| Affiliation: | 1. Department of Chemical Engineering Hanyang University Seoul 133‐791(Republic of Korea);2. Department of Materials Science and Engineering Hanyang University Seoul 133‐791(Republic of Korea);3. Department of Chemical Engineering Iwate University 4‐3‐5 Ueda, Morioka, Iwate 020‐8551 (Japan);4. Department of Chemical and Biological Engineering Illinois Institute of Technology 10?W. 33rd Street, Chicago, IL (USA);5. Electrochemical Technology Program Chemical Sciences and Engineering Division Argonne National Laboratory 9700 South Cass Avenue, Argonne, IL 60439 (USA) |
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| Abstract: | A high‐energy functional cathode material with an average composition of LiNi0.72Co0.18Mn0.10]O2, mainly comprising a core material LiNi0.8Co0.2]O2 encapsulated completely within a stable manganese‐rich concentration‐gradient shell is successfully synthesized by a co‐precipitation process. The LiNi0.72Co0.18Mn0.10]O2 with a concentration‐gradient shell has a shell thickness of about 1 µm and an outer shell composition rich in manganese, LiNi0.55Co0.15Mn0.30]O2. The core material can deliver a very high capacity of over 200 mA h g?1, while the manganese‐rich concentration‐gradient shell improves the cycling and thermal stability of the material. These improvements are caused by a gradual and continuous increase of the stable tetravalent Mn in the concentration‐gradient shell layer. The electrochemical and thermal properties of this cathode material are found to be far superior to those of the core LiNi0.8Co0.2]O2 material alone. Electron microscopy also reveals that the original crystal structure of this material remains intact after cycling. |
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| Keywords: | batteries core– shell materials electrochemistry electrodes lithium surface modification |
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