Room‐temperature (RT) sodium–sulfur (Na–S) batteries hold great promise for large‐scale energy storage due to the advantages of high energy density, low cost, and resource abundance. The research progress on RT Na–S batteries, however, has been greatly hindered by the sluggish kinetics of the sulfur redox reactions. Herein, an elaborate multifunctional architecture, consisting of N‐doped carbon skeletons and tunable MoS2 sulfiphilic sites, is fabricated via a simple one‐pot reaction followed by in situ sulfurization. Beyond the physical confinement and chemical binding of polarized N‐doped carbonaceous microflowers, the MoS2 active sites play a key role in catalyzing polysulfide redox reactions, especially the conversion from long‐chain Na2Sn (4 ≤ n ≤ 8) to short‐chain Na2S2 and Na2S. Significantly, the electrocatalytic activity of MoS2 can be tunable via adjusting the discharge depth. It is remarkable that the sodiated MoS2 exhibits much stronger binding energy and electrocatalytic behavior compared to MoS2 sites, effectively enhancing the formation of the final Na2S product. Consequently, the S cathode achieves superior electrochemical performance in RT Na–S batteries, delivering a high capacity of 774.2 mAh g−1 after 800 cycles at 0.2 A g−1, and an ultrahigh capacity retention with a capacity decay rate of only 0.0055% per cycle over 2800 cycles.

The anionic redox reaction (ARR) has attracted extensive attention due to its potential to enhance the reversible capacity of cathode materials in Li/Na‐ion batteries (LIBs/SIBs). However, the understanding of its activation mechanism is still limited by the insufficient mastering of the underlying thermodynamics and kinetics. Herein, a series of Mg/Li/Zn‐substituted NaxMnO2 and LixMnO2 cathode materials are designed to investigate their ARR behaviors. It is found that the ARR can be activated in only Li‐substituted LixMnO2 and not for Mg‐ and Zn‐substituted ones, while all Mg/Li/Zn‐substituted NaxMnO2 cathode materials exhibit ARR activities. Combining theoretical calculations with experimental results, such a huge difference between Li and Na cathodes is closely related to the migration of substitution ions from the transition metal layer to the alkali metal layer in a kinetic aspect, which generates unique Li(Na)–O–□TM and/or □Li/Na–O–□TM configurations and reducing reaction activation energy to trigger the ARR. Based on these findings, an ion‐migration mechanism is proposed to explain the different ARR behaviors between the NaxMnO2 and LixMnO2, which can not only reveal the origin of ARR in the kinetic aspect, but also provide a new insight for the development of high‐capacity metal oxide cathode materials for LIBs/SIBs.

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