Large volume change and grain pulverization are two major challenges of alloy-type anode materials for sodium ion batteries. Herein, we propose a soft covalent bonding confinement strategy for dispersing high capacity Sb into a robust and conductive Mo–S framework. The high capacity and high rate sodium storage are integrated into a single-phase Mo₂SbS₂ anode, in which atomic Sb is confined in a zig-zag Mo–S layer via soft Mo–Sb bonds. The robust and conductive Mo–S framework can effectively buffer the volume expansion of Sb during sodiation and provide an enhanced surface pseudocapacitive reaction for ultrafast sodium storage. This novel Mo₂SbS₂ anode can provide a high capacity of 373 mA h g⁻¹ at 0.6C and show an excellent rate performance and a long cycling life (289 mA h g⁻¹ at 30C and ∼90% capacity retention at 60C after 11 000 cycles). Interestingly, an intercalative-like sodiation process is observed from the in situ XRD patterns, in situ Raman spectra, ex situ TEM and XPS characterization. The integrity of the robust Mo–S framework can be confirmed after discharge. This soft covalent bonding confinement strategy can broaden the horizons of the design of anode materials for high energy density and power density of SIBs.

中文翻译：

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通过软共价键将原子锑固定在插层 Mo-S 框架中，用于快速充电和长寿命钠离子电池

大体积变化和晶粒粉化是钠离子电池合金型负极材料面临的两大挑战。在此，我们提出了一种软共价键限制策略，用于将高容量 Sb 分散到坚固且导电的 Mo-S 骨架中。高容量和高速率钠存储被集成到单相 Mo ₂ SbS ₂阳极中，其中原子 Sb通过软 Mo-Sb 键被限制在锯齿形 Mo-S 层中。坚固且导电的 Mo-S 框架可以有效缓冲 Sb 在钠化过程中的体积膨胀，并为超快钠储存提供增强的表面赝电容反应。这种新颖的 Mo ₂ SbS _{2阳极可提供 373 mA hg} ⁻¹的高容量在 0.6C 时表现出优异的倍率性能和长循环寿命（30C 时为 289 mA hg ^-1，11000次循环后在 60C 时容量保持率约为 90%）。有趣的是，从原位XRD 模式、原位拉曼光谱、非原位TEM 和 XPS 表征中观察到类似插层的钠化过程。放电后可以确认坚固的 Mo-S 框架的完整性。这种软共价键限制策略可以拓宽SIBs高能量密度和功率密度负极材料的设计视野。