One-pot synthesis of carbon coated Fe₃O₄ nanosheets with superior lithium storage capability

Hybrid nanosheet structures based on carbon coated metal oxides still attract promising interest as high-performance electrode materials for next-generation lithium-ion batteries (LIBs). In this study, we develop a simple one-pot solution method to synthesize large-scale flat Fe₃O₄ nanosheet hybrid structures coated with an amorphous carbon overlayer (denoted as Fe₃O₄@C NSs) followed by a thermal annealing treatment. It is found that the refluxing temperature plays an important role in adjusting the morphology of the Fe₃O₄@C hybrid. Increasing the temperature from 140 °C to 200 °C will lead to flower-like hybrid structures constructed by Fe₃O₄ nanoflakes gradually growing, rupturing, and finally evolving into flat and completely separate nanoflakes with large size at 200 °C. When evaluated as an anode material for LIBs, the hybrid Fe₃O₄@C NSs demonstrate a high reversible capacity of 1232 mA h g^-1 over 120 cycles at a current density of 200 mA g^-1, and remarkable rate capability.