Thin Carbon Layer Coated Porous Fe3O4 Particles Supported by rGO Sheets for Improved Stable Sodium Storage

Abstract

AbstractIron oxide (Fe3O4) is considered as a promising sodium ion anode material due to high capacity, low cost and nontoxic features. However, the main challenges associated with Fe3O4 anodes are structure instability and low initial Coulombic efficiency (∼50%) during charge/discharge process. In this work, thin carbon layer (∼2.5 nm) coated porous Fe3O4 particles (∼ 100 nm) anchored on reduced graphene oxide sheets (Fe3O4@C/rGO) are achieved. Fe3O4@C/rGO composite shows a stable cycling performance of 356 mAh g−1 after 300 cycles at 0.1 A g−1 with a slight decay of 0.098 mAh g−1 per cycle. Moreover, it exhibits a high initial Coubombic efficiency of 74%, superior to the values in most reported literatures for Fe3O4/carbon composites. The excellent electrochemical performance is attributed to the porous structure of Fe3O4 which can accommodate the mechanical stress induced by the volume expansion, and the outside carbon layers which can protect Fe3O4 from electrolyte to form a stable solid electrolyte interface film.