Synergistic Effects of Confinement Structure and Local‐Expanded Interlayer Spacing in Fe<sub>2</sub>Mo<sub>3</sub>O<sub>8</sub>@C@MoS<sub>2</sub> Toward High‐Efficient Sodium Ion Storage
Yifan Tang, Guochang Li, Shuangxing Cui, Wan Cui, Hui Chong, Lei Han, Huan Pang
Abstract
Abstract 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 Fe 2 Mo 3 O 8 @C@MoS 2 with local‐expanded interlayer spacing is designed via high‐temperature phase transition from FeMoO 4 to Fe 2 Mo 3 O 8 and the tactically introducing dopamine molecules into the interlayer of MoS 2 nanosheets. By analysis of the in situ generated solid electrolyte interphase film in different electrolytes, the favorable compatibility of Fe 2 Mo 3 O 8 @C@MoS 2 in ether‐based electrolytes is well illustrated. Importantly, the sodium storage mechanism and detailed structural evolution of Fe 2 Mo 3 O 8 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 Fe 2 Mo 3 O 8 @C@MoS 2 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 Fe 2 Mo 3 O 8 and a promising strategy for constructing high‐performance anodes for SIBs.