The anionic redox activity in lithium‐rich layered oxides has the potential to boost the energy density of lithium‐ion batteries. Although it is widely accepted that the anionic redox activity stems from the orphaned oxygen energy level, its regulation and structural stabilization, which are essential for practical employment, remain still elusive, requiring an improved fundamental understanding. Herein, the oxygen redox activity for a wide range of 3d transition‐metal‐based Li₂TMO₃ compounds is investigated and the intrinsic competition between the cationic and anionic redox reaction is unveiled. It is demonstrated that the energy level of the orphaned oxygen state (and, correspondingly, the activity) is delicately governed by the type and number of neighboring transition metals owing to the π‐type interactions between LiOLi and M t_2g states. Based on these findings, a simple model that can be used to estimate the anionic redox activity of various lithium‐rich layered oxides is proposed. The model explains the recently reported significantly different oxygen redox voltages or inactivity in lithium‐rich materials despite the commonly observed LiOLi states with presumably unhybridized character. The discovery of hidden factors that rule the anionic redox in lithium‐rich cathode materials will aid in enabling controlled cumulative cationic and anionic redox reactions.

中文翻译：

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过渡金属调节富锂层状氧化物中的阴离子氧化还原活性

富含锂的层状氧化物中的阴离子氧化还原活性具有提高锂离子电池能量密度的潜力。尽管人们普遍认为阴离子氧化还原活性源于孤氧能级，但对于实际应用而言必不可少的调节和结构稳定作用仍然难以捉摸，需要进一步的基本了解。在此，对于3 d过渡金属基Li ₂ TMO ₃，氧的氧化还原活性对化合物进行了研究，揭示了阳离子和阴离子氧化还原反应之间的内在竞争。据证实孤立氧态的能量水平（和，相应地，活性）由相邻由于锂之间的π型相互作用的过渡金属的类型和数量微妙地支配 ö 李和M吨_2克状态。基于这些发现，提出了一个可用于估算各种富锂层状氧化物的阴离子氧化还原活性的简单模型。该模型解释了富锂材料最近报道显著不同的氧的氧化还原电压或不活动，尽管通常观察到的李 Ò 李说其性格未杂。在富锂阴极材料中发现决定阴离子氧化还原的隐藏因素的发现，将有助于实现受控的累积阳离子和阴离子氧化还原反应。