A corn-inspired structure design for an iron oxide fiber/reduced graphene oxide composite as a high-performance anode material for Li-ion batteries

Abstract

In this paper, we successfully synthesized iron oxide (Fe₂O₃) fiber/reduced graphene oxide (rGO) composites with a “corn” structure by an electrospinning technique assisted by annealing treatment and a far infrared reduction process. The special structure consists of Fe₂O₃ fibers as the “corncob” completely protected by multilayer rGO as the “sepal”. Natural void space between the Fe₂O₃ fibers and rGO allows for the expansion of Fe₂O₃ upon lithiation; the good surface area and unblocked channels in the Fe₂O₃ fiber facilitates fast diffusion of Li⁺. An electrode with such structure shows excellent capacity (1085.2 mA h g⁻¹ at 0.1 A g⁻¹), and cycle life (407.8 mA h g⁻¹ at 5 A g⁻¹ for 1500 cycles with good coulombic efficiency). This is the longest cycle life for Fe₂O₃-based anode materials with excellent rate capability (e.g., >400 mA h g⁻¹ at 5 A h g⁻¹). In addition to Fe₂O₃, this “corn” structure can also be applied to other high capacity anode materials for next generation Li-ion batteries to improve cycle life and coulombic efficiency.