Facile synthesis of Fe3O4 ultrathin layer coated Fe2O3 composite anode for enhanced lithium-ion storage

Fe₂O₃ has been considered as a promising anode material for lithium-ion batteries (LIBs) owing to its high specific capacity. However, its sluggish charge transfer resulting from the poor electrical conductivity severely limits the electrochemical performance. In this work, an ultrathin Fe₃O₄ layer-coated Fe₂O₃ composite was fabricated through a facile one-step hydrothermal method with hydrazine hydrate as the reductant in an alkaline environment. Upon use as the anode for LIBS, the as-resulted Fe₂O₃@Fe₃O₄ composite achieves a high specific capacity of 1539.5 mA h g⁻¹ at a current density of 100 mA g⁻¹ and simultaneously maintains a high discharge capacity of 707.8 mAh g⁻¹ after 800 cycles at 1000 mA g⁻¹, outperforming the commercial Fe₂O₃ sample. Electrochemical characterizations reveal that the improved electrochemical performance can be attributed to the combined effects of higher theoretical specific capacity of Fe₂O₃ and superior electrical conductivity of Fe₃O₄.