材料科学
氧化还原
氧化物
金属
阴极
配体(生物化学)
电荷(物理)
航程(航空)
电压
无机化学
电气工程
物理化学
化学
复合材料
冶金
受体
生物化学
物理
量子力学
工程类
作者
Anchun Tang,Ruixuan Zhao,Yuan Wu,ChuBin Wan,Zhengyao Li,Xianhe Meng,Kai Sun,Ruikai Li,Hexiang Zhang,Dongfeng Chen,Xin Ju
标识
DOI:10.1002/adfm.202402639
摘要
Abstract Anionic redox in layered transition metal oxides (TMOs) cathodes presents significant opportunities for achieving high energy density batteries. However, the O 2p non‐bonding state can only undergo redox at high voltages and is often accompanied by severe structural distortion. In this study, the whole‐voltage‐range anionic redox has successfully been achieved in Metal‐organic frameworks (MOF) derived chemically homogeneous P2‐Na 0.67 Ni 0.2 Mg 0.2 Mn 0.6 O 2 (NNMMO). Through a systematic analysis of the orbital combinations of TMs and O, it is found that the Mg‐induced O 2p non‐bonding state as an electron donor, forming strong π‐type interactions between Ni 3d spin‐down t 2g orbitals. The resulting π‐configurational oxygen occupies an anti‐bonding state just below the Fermi level, exhibiting high oxidation activity and stability. Additionally, the high covalency between Mn and O increases the strength of the Mn–O bond, mitigating the structural aberration of NNMMO. As a result, NNMMO demonstrates a high capacity of 216 mAh g −1 at 0.1 C and stable battery performance, with a capacity retention of ≈90% after 500 cycles at 2 C. This π‐type anionic redox and intrinsic competition mechanism present an alternative strategy for achieving advanced cathode materials for sodium‐ion batteries.
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