Synthesis of core-shell carbon encapsulated Fe2 O3 composite through a facile hydrothermal approach and their application as anode materials for sodium-ion batteries

Abstract

Carbon encapsulated Fe2 O3 nanoparticles (C@Fe2 O3) were successfully synthesized via a facile and environmentally friendly hydrothermal method and prototyped in anode materials for sodium ion batteries (SIBs). High-resolution transmission and scanning electronic microscopy observations exhibited the formation of a highly core-shelled C@Fe2 O3 composite consisting of carbon layers coated onto uniform Fe2 O3 nanoparticles with a median diameter of 46.1 nm. This core-shell structure can repress the aggregation of Fe2 O3 nanoparticles, preventing the harsh volume change of the electrode, enhancing the electric conductivity of the active materials, and promoting Na-ion transformation during cycling. The electrochemical performances of the C@Fe2 O3 composite, as anodes for SIBs, retained a reversible capacity of 305 mAh g−1 after 100 cycles at 50 mA g−1 and exhibited an excellent cyclability at various current densities due to the synergistic effect between the carbon layers and Fe2 O3. These results suggest that C@Fe2 O3 composites present much potential as anode materials for rechargeable SIBs.