Aligned Ferric Oxide/Graphene with Strong Coupling Effect for High-Performance Anode

Herein, the strong coupling effect on the atomic scale and the aligned structure on microscale are introduced simultaneously to establish a superior ferric oxide/graphene anode. The strong coupling between graphene and ferric oxide (Fe3O4) is established by the high-temperature and long-term in situ hydrothermal reduction. The aligned architecture is elaborately introduced by an upward magnetostatic field. The strong coupling effect enhances the adsorption for a lithium ion (Li+) and conductivity due to the formation of an imbalanced electric field. In terms of the aligning architecture, the loosely vertical-aligned Fe3O4/reduced graphene oxide hybrid (vertical to the current collector) induced by an upward magnetostatic field minimizes the Li+ diffusion tortuosity, lowers the Li+ diffusion barrier, and relaxes the volume stress. Therefore, the vertical-reduced graphene oxide/Fe3O4 composite electrode shows an excellent performance, such as 610 mA h g–1 at 10 A/g and about 700 mA h g–1 at 3 A/g after 1000 cycles. The in-deep enhanced mechanism is explored and confirmed by experiments and density functional theory calculations. This work provides an available design thinking for advanced anodes.