Ning Fanghua, Li Biao, Song Jin, Zuo Yuxuan, Shang Huaifang, Zhao Zimeng, Yu Zhen, Chu Wangsheng, Zhang Kun, Feng Guang, Wang Xiayan, Xia Dingguo
Beijing Key Laboratory of Theory and Technology for Advanced Batteries Materials, College of Engineering, Peking University, Beijing, 100871, People's Republic of China.
Department of Chemistry and Chemical Engineering, Beijing University of Technology, Beijing, 100124, People's Republic of China.
Nat Commun. 2020 Oct 2;11(1):4973. doi: 10.1038/s41467-020-18423-7.
Li-rich layered oxide cathode materials show high capacities in lithium-ion batteries owing to the contribution of the oxygen redox reaction. However, structural accommodation of this reaction usually results in O-O dimerization, leading to oxygen release and poor electrochemical performance. In this study, we propose a new structural response mechanism inhibiting O-O dimerization for the oxygen redox reaction by tuning the local symmetry around the oxygen ions. Compared with regular LiRuO, the structural response of the as-prepared local-symmetry-tuned LiRuO to the oxygen redox reaction involves the telescopic O-Ru-O configuration rather than O-O dimerization, which inhibits oxygen release, enabling significantly enhanced cycling stability and negligible voltage decay. This discovery of the new structural response mechanism for the oxygen redox reaction will provide a new scope for the strategy of enhancing the anionic redox stability, paving unexplored pathways toward further development of high capacity Li-rich layered oxides.
富锂层状氧化物正极材料由于氧氧化还原反应的贡献，在锂离子电池中表现出高容量。然而，这种反应的结构适应性通常会导致O-O二聚化，从而导致氧释放和较差的电化学性能。在本研究中，我们提出了一种新的结构响应机制，通过调节氧离子周围的局部对称性来抑制氧氧化还原反应中的O-O二聚化。与常规LiRuO相比，所制备的局部对称性调谐LiRuO对氧氧化还原反应的结构响应涉及伸缩的O-Ru-O构型，而不是O-O二聚化，这抑制了氧释放，从而显著提高了循环稳定性，且电压衰减可忽略不计。这种氧氧化还原反应新结构响应机制的发现将为增强阴离子氧化还原稳定性的策略提供新的空间，为高容量富锂层状氧化物的进一步发展开辟未探索的途径。
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