High performance porous iron oxide-carbon nanotube nanocomposite as an anode material for lithium-ion batteries

Highlights: • Fe₃O₄-carbon nanotubes (CNTs) composites were synthesized in non-aqueous media by reflux method. • Fe₃O₄ nanoparticles were dispersed on the surface of CNTs homogeneously. • Porous structure accommodates the large volume change of Fe₃O₄ component. • The 3D CNTs conductive network improves the electric conductivity. • Fe₃O₄-CNTs-80 showed a high discharge capacity of 930 mA h g⁻¹ at 100th cycle. - Abstract: Here, we showed that relatively high content of Fe₃O₄ nanoparticles (up to 83 wt. %) can be homogeneously dispersed into carbon nanotubes (CNTs) conductive networks using non-aqueous media by refluxing method. Three different Fe₃O₄-CNTs composites were prepared, i.e., Fe₃O₄-CNTs-50, Fe₃O₄-CNTs-80 and Fe₃O₄-CNTs-90 that contain increasing amount of Fe₃O₄ from 50 wt. % to 83 wt. % and to 89 wt. %. These composites have higher surface area and higher pore volume than Fe₃O₄ component due to CNTs content. The best composite, i.e., Fe₃O₄-CNTs-80 demonstrated negligible capacity loss up to 100 cycles and high discharge capacity of 930 mA h g⁻¹ at 100th cycle and 100 mA g⁻¹ current discharge rate. This composite also exhibited excellent rate capability where up to the 78.8% of original capacity can be retained at high current discharge rate of 1000 mA g⁻¹. These performances were enabled by a unique porous architecture based on homogenous dispersion of Fe₃O₄ nanoparticles into CNTs networks that leads to short Li⁺ diffusion path, high electric conductivity and buffering space to accommodate large volume change of Fe₃O₄ component during the charge-discharge processes.