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Unveiling the High-valence Oxygen Degradation Across the Delithiated Cathode Surface |
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| Authors: | Prof Qinghao Li Qi Liang Dr Hui Zhang Sichen Jiao Dr Zengqing Zhuo Dr Junyang Wang Prof Qiang Li Prof Jie-Nan Zhang Prof Xiqian Yu |
| Institution: | 1. College of Physics, Center for Marine Observation and Communications, Qingdao University, Qingdao, 266071 China
Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190 China These authors contributed equally to this work.;2. College of Physics, Center for Marine Observation and Communications, Qingdao University, Qingdao, 266071 China These authors contributed equally to this work.;3. State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050 China;4. Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190 China;5. Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA;6. College of Physics, Center for Marine Observation and Communications, Qingdao University, Qingdao, 266071 China |
| Abstract: | Charge compensation on anionic redox reaction (ARR) has been promising to realize extra capacity beyond transition metal redox in battery cathodes. The practical development of ARR capacity has been hindered by high-valence oxygen instability, particularly at cathode surfaces. However, the direct probe of surface oxygen behavior has been challenging. Here, the electronic states of surface oxygen are investigated by combining mapping of resonant Auger electronic spectroscopy (mRAS) and ambient pressure X-ray photoelectron spectroscopy (APXPS) on a model LiCoO2 cathode. The mRAS verified that no high-valence oxygen can sustain at cathode surfaces, while APXPS proves that cathode electrolyte interphase (CEI) layer evolves and oxidizes upon oxygen gas contact. This work provides valuable insights into the high-valence oxygen degradation mode across the interface. Oxygen stabilization from surface architecture is proven a prerequisite to the practical development of ARR active cathodes. |
| Keywords: | Anionic Redox Reaction Cathode Electrolyte Interphase Lithium-Ion Batteries X-Ray Spectroscopy |