Metal germanium (Ge) with a high theoretical capacity of 590 mA h g⁻¹ is regarded as a promising anode material for sodium ion batteries, but it suffers from a fast capacity decay problem due to the serious agglomeration of Ge particles caused by the drastic volume change during the sodiation/desodiation process. Constructing highly dispersed ultrafine Ge nanoparticles is a possible way to address this problem. However, reported methods to obtain highly dispersed metal nanoparticles encountered problems of poor electrochemical activity or non-uniform particle size. In this work, we proposed a new in situ confined polymerization method for preparing highly dispersed Ge quantum dots (QDs). Due to the high dispersion of Ge QDs in carbon frameworks derived from poly(ionic liquid) networks, the obtained Ge@C nanocomposite could effectively avoid the agglomeration of Ge particles. When applied as the anode material for sodium ion batteries, the Ge@C nanocomposite shows ultra-long cycle life and high rate capability. At a current density of 1500 mA g⁻¹, the Ge@C electrode could display a high capacity of 201 mA h g⁻¹ after 5000 cycles. This method could be extended to prepare other highly dispersed metal nanoparticles and achieve fairly efficient electrode materials for new-type secondary batteries.

中文翻译：

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用于超长寿命钠离子电池的碳骨架中高度分散的Ge量子点

具有 590 mA hg ^-1高理论容量的金属锗 (Ge)被认为是一种很有前途的钠离子电池负极材料，但由于剧烈的体积导致 Ge 颗粒严重团聚，因此存在容量衰减快的问题在钠化/脱钠过程中发生变化。构建高度分散的超细锗纳米粒子是解决这个问题的一种可能方法。然而，已报道的获得高度分散的金属纳米粒子的方法遇到了电化学活性差或粒度不均匀的问题。在这项工作中，我们提出了一种新的原位用于制备高度分散的Ge量子点（QD）的受限聚合方法。由于Ge量子点在聚（离子液体）网络衍生的碳骨架中的高度分散，获得的Ge@C纳米复合材料可以有效避免Ge颗粒的团聚。当用作钠离子电池的负极材料时，Ge@C 纳米复合材料显示出超长的循环寿命和高倍率性能。在 1500 mA g ^-1的电流密度下，Ge@C 电极在 5000 次循环后可显示出 201 mA hg ^-1的高容量。这种方法可以扩展到制备其他高度分散的金属纳米粒子，并获得相当有效的新型二次电池电极材料。