Abstract Fe3Se4 nanoparticles confined in hollow and self-supported carbon nanocages are synthesized for the first time through facile Fe3O4 nanospheres precursor etching couple with a following selenization process. The as-obtained Fe3Se4@C nanocages exhibit excellent sodium storage performance as sodium-ion battery anodes. The remarkable electrochemical properties are attributed to the high specific capacity of Fe3Se4 on top of the specially-designed nanocage architecture, in which the sufficient internal void space between the Fe3Se4 nanoparticles and the carbon shell accommodates the volume variation of Fe3Se4 to avoid and deforming the carbon shell as well as the entire composite nanostructure. The presence of the highly conductive carbon shells facilitate fast electron and Na+ ion transportation to promote continuous sodiation and desodiation. Benefiting from this unique nanostructure, the composite delivers a stable high specific capacity of 544.1 mAh g−1 at 200 mA g−1 after 100 charge/discharge cycles. Furthermore, a stable capacity of 402.2 mAh g−1 is retained at 2000 mA g−1 after 200 cycles. Meanwhile, a high specific capacity of 328.7 mAh g−1 is achieved at the extraordinary current density of 5000 mA g−1, manifesting an outstanding sodium storage performance.

中文翻译：

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Fe3Se4纳米颗粒限制在用于高性能钠离子电池的空心碳纳米笼中

摘要 通过简单的 Fe3O4 纳米球前驱体蚀刻和后续的硒化过程，首次合成了限制在空心自支撑碳纳米笼中的 Fe3Se4 纳米粒子。所获得的 Fe3Se4@C 纳米笼作为钠离子电池负极表现出优异的储钠性能。卓越的电化学性能归因于 Fe3Se4 在特殊设计的纳米笼结构之上的高比容量，其中 Fe3Se4 纳米颗粒和碳壳之间足够的内部空隙空间容纳 Fe3Se4 的体积变化，以避免和变形碳壳以及整个复合纳米结构。高导电碳壳的存在促进了电子和 Na+ 离子的快速传输，从而促进了连续的钠化和脱钠。受益于这种独特的纳米结构，该复合材料在 100 次充电/放电循环后在 200 mA g-1 下可提供 544.1 mAh g-1 的稳定高比容量。此外，在 200 次循环后，402.2 mAh g-1 的稳定容量保持在 2000 mA g-1。同时，在 5000 mA g-1 的超常电流密度下实现了 328.7 mAh g-1 的高比容量，表现出出色的储钠性能。