Crosslinking-induced spontaneous growth: A novel strategy for synthesizing sandwich-type graphene@Fe 3O 4 dots/amorphous carbon with high lithium storage performance

摘要

Graphical abstractDisplay OmittedHighlights?Crosslinking-induced spontaneous growth is developed for preparing G@Fe3O4/C.?G@Fe3O4/C shows sandwich-type structure with ultrasmall Fe3O4dots of 2–3?nm.?G@Fe3O4/C presents highly reversible capacity and superior high-rate capability.AbstractGraphene/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).]]>