Doping engineering is considered as a key approach to develop catalysts for Li-S batteries that can mediate redox reaction and chemisorption immobilization of polysulfides. However, the rationalization of doping elements selection and the intrinsic regulatory essences remain elusive. Herein, we propose a sensible strategy of modulating the electron-filled state of d-orbital of the Ni elements to accelerate redox dynamics of polysulfides. Concretely, we introduce dopants (V or Mn) that feature empty or half-filled vacant 3d orbitals to substitute partial cations of NiP. The analysis confirms that the electrons of Ni 3d orbitals can be transferred to the doped atoms with unoccupied orbitals, resulting in a reduced electron-filling number of the Ni 3d orbitals. Notably, the electrons are more inclined to transfer to V with empty orbitals compared to Mn with partially occupied orbitals. More importantly, we delineate the relationship between electron-filled state of the Ni 3d orbitals and polysulfides adsorption-catalytic activity as well as corresponding intrinsic mechanism. Benefiting from the above advantages, the cell with V-NiP separator can achieve a discharge capacity of 1052 mAh g at high sulfur loading (5.4 mg cm) and lean electrolyte (E/S = 6 μL mg) condition. This work illustrates essential link between d-electron filling state of metal atoms and adsorption-catalytic activity of polysulfides, which provides a pointer for rational selection of doping elements.

中文翻译：

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通过阳离子掺杂重新分布 Ni2P 中的 d 轨道态来加速硫氧化还原动力学，用于高性能锂硫电池

掺杂工程被认为是开发可介导氧化还原反应和多硫化物化学吸附固定的锂硫电池催化剂的关键方法。然而，掺杂元素选择的合理性和内在的监管本质仍然难以捉摸。在此，我们提出了一种合理的策略，即调节 Ni 元素 d 轨道的电子填充状态，以加速多硫化物的氧化还原动力学。具体来说，我们引入具有空或半填充的空 3d 轨道的掺杂剂（V 或 Mn）来替代 NiP 的部分阳离子。分析证实Ni 3d 轨道的电子可以转移到未占据轨道的掺杂原子上，导致Ni 3d 轨道的电子填充数减少。值得注意的是，与部分占据轨道的 Mn 相比，电子更倾向于转移到空轨道的 V。更重要的是，我们描述了Ni 3d轨道的电子填充状态与多硫化物吸附催化活性之间的关系以及相应的内在机制。受益于上述优点，采用V-NiP隔膜的电池在高硫负载量（5.4 mg cm）和贫电解液（E/S = 6 μL mg）条件下可实现1052 mAh g的放电容量。该工作阐明了金属原子的d电子填充状态与多硫化物的吸附催化活性之间的本质联系，为合理选择掺杂元素提供了指导。