A novel Fe_2O_3 rhombohedra/graphene composite as a high stability electrode for lithium-ion batteries

摘要

We demonstrate in this paper the shape-controlled synthesis of α-Fe_2O_3 rhombohedra anchored graphene nanocomposites through a simple hydrothermal strategy by adopting inorganic species in the synthesis system. TEM investigations reveal that the rhombohedra with an average diameter of 80 nm is formed through oriented attachment of primary nanocrystals assisted by Ostwald ripening, and CH_3COONa inorganic surfactant played an important role in control over the final morphology of the products. As high-performance anodes for lithium-ion batteries, the obtained Fe_2O_3 rhombohedra/graphene composite exhibits the first reversible capacity of 905.3 mAh g~(-1), and high capacity retention of 85.7% after 50 cycles. These values are much higher than those of bare Fe_2O_3 and Fe_2O_3 particle/graphene composites, indicating its excellent electrochemical stability. These results give us a guideline for the study of the morphology-dependent properties of functional oxide materials as well as further applications for magnetic materials, lithium-ion batteries, and gas sensors.