Sodium‐ion batteries (SIBs) are considered as a promising alternative to lithium‐ion batteries, due to the abundant reserves and low price of Na sources. To date, the development of anode materials for SIBs is still confronted with many serious problems. In this work, encapsulation‐type structured MoSe₂@hollow carbon nanosphere (HCNS) materials assembled with expanded (002) planes few‐layer MoSe₂ nanosheets confined in HCNS are successfully synthesized through a facile strategy. Notably, the interlayer spacing of the (002) planes is expanded to 1.02 nm, which is larger than the intrinsic value of pristine MoSe₂ (0.64 nm). Furthermore, the few‐layer nanosheets are space‐confined in the inner cavity of the HCNS, forming hybrid MoSe₂@HCNS structures. When evaluated as anode materials for SIBs, it shows excellent rate capabilities, ultralong cycling life with exceptional Coulombic efficiency even at high current density, maintaining 501 and 471 mA h g⁻¹ over 1000 cycles at 1 and 3 A g⁻¹, respectively. Even when cycled at current densities as high as 10 A g⁻¹, a capacity retention of 382 mA h g⁻¹ can be achieved. The expanded (002) planes, 2D few‐layer nanosheets, and unique carbon shell structure are responsible for the ultralong cycling and high rate performance.

中文翻译：

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很少层的MoSe2纳米片具有扩展的（002）平面，限制在空心碳纳米球中，用于超高性能钠离子电池

钠离子电池（SIB）被认为是锂离子电池的有前途的替代品，因为其钠离子源储量丰富且价格低廉。迄今为止，用于SIB的阳极材料的开发仍然面临许多严重的问题。在这项工作中，通过一种简便的策略成功地合成了封装型结构化的MoSe ₂ @空心碳纳米球（HCNS）材料，该材料与扩展的（002）平面，限制在HCNS中的几层MoSe ₂纳米片组装在一起。值得注意的是，（002）平面的层间间距扩大到1.02 nm，大于原始MoSe ₂的本征值（0.64 nm）。此外，几层纳米片被空间限制在HCNS的内腔中，形成杂化的MoSe ₂@HCNS结构。当评估为SIB的阳极材料时，它显示出出色的速率能力，超长循环寿命以及即使在高电流密度下也具有出色的库仑效率，在1和3 A g ^-1的1000次循环中分别保持501和471 mA hg ^-1。即使当以高达10 A g ^-1的电流密度循环时，也可以实现382 mA hg ^-1的容量保持率。扩展的（002）平面，2D多层纳米片和独特的碳壳结构是超长循环和高倍率性能的原因。