Crosslinking-induced spontaneous growth: A novel strategy for synthesizing sandwich-type graphene@Fe 3 O 4 dots/amorphous carbon with high lithium storage performance
Crosslinking-induced spontaneous growth: A novel strategy for synthesizing sandwich-type graphene@Fe 3 O 4 dots/amorphous carbon with high lithium storage performance
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DOI：
10.1016/j.cej.2017.11.142
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发表时间：
2018-02
影响因子：
15.1
通讯作者：
Chengfei Li;Zhao-peng Li;Xiaoji Ye;Xiao‐Qing Yang;Guoqing Zhang;Zhenghui Li
中科院分区：
文献类型：
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作者：
Chengfei Li;Zhao-peng Li;Xiaoji Ye;Xiao‐Qing Yang;Guoqing Zhang;Zhenghui Li
石墨烯/Fe 3 O 4杂化材料一直被认为是锂离子电池的理想负极材料，但在重复锂化/脱锂过程中，Fe 3 O 4颗粒尺寸不均匀、团聚等问题仍然是制约石墨烯/Fe 3 O 4杂化材料性能的主要瓶颈。通过仔细选择二茂铁的金属有机分子作为结构单元，本文探索了一种通过Friedel-Crafts交联诱导的自发生长过程制备纳米型石墨烯@Fe3O4点/无定形碳（G@Fe3O4/C）杂化物的新方法。所制备的石墨烯表面包覆的无定形碳基体中均匀分布着2-3 nm的超小Fe 3 O 4点。超小尺寸的Fe 3 O 4点能够最小化体积变化和Li+迁移距离，而碳基质和石墨烯框架防止Fe 3 O 4点聚集并提供上级导电骨架沿着柔性框架以缓冲体积变化。此外，发达的孔结构可以适应大的体积变化并促进电解质扩散/转移，从而增加离子可及表面积，特别是在高充放电速率下。因此，G@Fe3O4/C表现出优异的锂存储性能，包括1241 mAh g-1的高可逆容量、200次循环后的出色循环稳定性（1055 mAh g-1）和上级的高倍率容量（5A g-1时724 mAh g-1）。
Graphene/Fe3O4hybrids have long been regarded as promising anode materials for lithium-ion batteries but remain significant bottlenecks of inhomogeneous/large Fe3O4particle size and agglomeration during the repeated lithiation/dethiation process. By carefully selecting a metallo-organic molecule of ferrocene as the building block, a novel methodology has been explored herein for the preparation of sandwich-type graphene@Fe3O4dots/amorphous carbon (G@Fe3O4/C) hybrids via a Friedel–Crafts crosslinking-induced spontaneous growth process. As prepared, ultra-small Fe3O4dots of 2–3 nm are distributed uniformly in the amorphous carbon matrix coated on the surface of graphene. The ultralow size of Fe3O4dots is able to minimize the volume change and Li+migrating distance, while the carbon matrix and graphene framework prevent Fe3O4dots from aggregation and offer a superior conductive skeleton along with a flexible framework to buffer the volume changes. In addition, the well-developed pore structure can accommodate the large volume change and facilitate the electrolyte diffusion/transfer, thereby increasing the ion accessible surface area, especially at high charge–discharge rates. Consequently, G@Fe3O4/C presents excellent lithium storage performances, including a highly reversible capacity of 1241 mAh g−1, an outstanding cycling stability after 200 cycles (1055 mAh g−1) and a superior high-rate capability (724 mAh g−1at 5 A g−1).