Developing multicomponent composite materials with delicate morphology and tailored structure is of vital importance for designing advanced sodium‐ion batteries (SIBs). Herein, a confinement‐structured Fe2Mo3O8@C@MoS2 with local‐expanded interlayer spacing is designed via high‐temperature phase transition from FeMoO4 to Fe2Mo3O8 and the tactically introducing dopamine molecules into the interlayer of MoS2 nanosheets. By analysis of the in situ generated solid electrolyte interphase film in different electrolytes, the favorable compatibility of Fe2Mo3O8@C@MoS2 in ether‐based electrolytes is well illustrated. Importantly, the sodium storage mechanism and detailed structural evolution of Fe2Mo3O8 are established for the first time by in situ X‐ray diffraction. Furthermore, theoretical calculations indicate the unique structure facilitates internal charge transfer and enhances Na+ adsorption ability. Thanks to the unique confinement structure, local‐expanded interlayers and robust framework, the Fe2Mo3O8@C@MoS2 composite achieves a high reversible specific capacity of 636 mAh g‒1 at 0.1 A g‒1, excellent rate capability (301 mAh g‒1 at 5.0 A g‒1) and ultralong cycling stability (365 mAh g–1 after 6000 cycles at 2.0 A g–1). The study provides an essential understanding of the Na storage mechanism of Fe2Mo3O8 and a promising strategy for constructing high‐performance anodes for SIBs.

中文翻译：

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Fe2Mo3O8@C@MoS2 中约束结构和局部扩展层间距对高效钠离子存储的协同作用

开发具有精致形态和定制结构的多组分复合材料对于设计先进钠离子电池（SIB）至关重要。在此，限域结构的 Fe2莫3氧8@C@MoS22通过 FeMoO 的高温相变设计具有局部扩大的层间距4至铁2莫3氧8以及战术性地将多巴胺分子引入MoS2的层间2纳米片。通过对不同电解质中原位生成的固体电解质界面膜的分析，Fe的良好相容性2莫3氧8@C@MoS22在醚基电解质中的情况得到了很好的说明。重要的是，钠的储存机制和铁的详细结构演化2莫3氧8首次通过原位X射线衍射建立。此外，理论计算表明独特的结构有利于内部电荷转移并增强Na+吸附能力。由于独特的限制结构、局部膨胀的夹层和坚固的框架，Fe2莫3氧8@C@MoS22复合材料实现了636 mAh g的高可逆比容量−10.1 A g 时−1，优异的倍率性能（301 mAh g−15.0 A g 时−1）和超长循环稳定性（365 mAh g–12.0 A g 下 6000 次循环后–1）。该研究为铁的钠存储机制提供了重要的理解2莫3氧8以及构建 SIB 高性能阳极的有前景的策略。