氧化还原
氧气
钠
阴极
插层(化学)
化学
电化学
上部结构
析氧
无机化学
电极
有机化学
物理化学
海洋学
地质学
作者
Na Li,Enyue Zhao,Zhigang Zhang,Huaican Chen,Bao-Tian Wang,Xiaoling Xiao
标识
DOI:10.1016/j.cej.2023.143145
摘要
Manganese-based layered transition metal (TM) oxides with anionic redox reaction (ARR) activity hold great promise for low-cost and high-energy–density sodium-ion batteries cathodes. However, the unstable ARR charge compensation readily causes cycled capacity loss and voltage decay which severely restrict these materials’ commercial applications. Here, we show that a de-clustered distribution of nonbonding oxygen 2p state can enhance the stability of ARR and meanwhile increase its activity. The de-clustered nonbonding oxygen 2p state is achieved through regulating the ordered degree of cationic distributions that is superstructure in the TM layer. The designed cathode with relatively intact superstructure shows a record ARR activity and significantly suppressed voltage decay (0.52 mV per cycle). In-situ Raman indicates that the de-clustered nonbonding oxygen 2p state leads to an inhibited oxygen dimerization which is critical for stabilizing the ARR. Through employing in-situ X-ray diffraction, we reveal that the eliminated O–O dimers suppresses detrimental P2-P2′ phase transitions, leading to an ultralow volume change of 0.24% upon cycling. The robust Na-de/intercalation structure accompanying ARR process is further supported by theoretical calculations.
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