Confined metal Ge quantum dots in carbon nanofibers for stable rechargeable batteries
Confined metal Ge quantum dots in carbon nanofibers for stable rechargeable batteries
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碳纳米纤维中的受限金属Ge量子点用于稳定的可充电电池
DOI：
10.1039/c8nr00153g
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发表时间：
2018-04-21
期刊：
影响因子：
6.7
通讯作者：
Guo, Lin
中科院分区：
文献类型：
--
作者：
Wei, Wei;Wang, Hua;Guo, Lin
作为一种有前景的可充电电池合金型负极材料，金属锗（Ge）显示出高容量，但由于锂化/脱锂循环过程中体积膨胀较大，导致其容量快速衰减。在这项研究中，我们通过一种简便的静电纺丝方法，优化了Ge量子点（QD）和碳纳米纤维（CNF）的组合结构。具体来说，直径为4-7 nm的Ge QDs高度分散在多孔（孔径10-150 nm）CNF中。杂化的Ge/CNF纳米复合材料表现出优异的锂存储性能，如高可逆容量（200 mA g(-1)电流密度下为1204 mAh g(-1)）、高容量保持率（100次循环后为87.1%）和优异的倍率性能（3000 mA g(-1)电流密度下为760 mAh g(-1)）。电化学性能的提高归因于Ge QDs和碳纳米纤维的协同效应；这有效缓解了体积膨胀问题，防止了Ge的团聚，保持了纳米复合材料的结构稳定性，并改善了Li离子扩散的电极动力学。
As a promising alloy-type anode material for rechargeable batteries, the metal germanium (Ge) shows high capacity, but it suffers from a fast capacity fading problem caused by a large volume expansion during lithiation/delithiation cycles. In this study, via a facile electrospinning method, we optimized the combination structure of Ge quantum dots (QDs) and carbon nanofibers (CNFs). Specifically, Ge QDs with a diameter of 4-7 nm were highly dispersed in porous (pore size 10-150 nm) CNFs. The hybridized Ge/CNF nanocomposite exhibited remarkable Li storage performances such as high reversible capacity (1204 mA h g(-1) at a current density of 200 mA g(-1)), high capacity retention (87.1% after 100 cycles) and excellent rate property (760 mA h g(-1) at 3000 mA g(-1)). The improved electrochemical performance was due to the synergistic effects of Ge QDs and carbon nanofibers; this effectively alleviated the volume expansion problem, prevented the agglomeration of Ge, maintained the structural stability of the nanocomposite, and improved the electrode kinetics of diffusion of Li ions.