Rapid in-situ fabrication of Fe 3 O 4 /Fe 7 S 8 @C composite as anode materials for lithium-ion batteries

Fe 3 O 4 is currently one of the research hotspot of anode materials used in lithium-ion batteries because of its high theoretical lithium storage capacity, abundant in nature, low cost and environmental-friendly. However, problems such as poor electron conductivity and large volume change during lithium transfer often lead to deterioration of electrochemical performance which limits their practical application. Here, with a designed composite of Fe 3 O 4 /Fe 7 S 8 supported by carbon skeleton, we used a facile and rapid rheological phase method to realize the in-situ construction of the Fe 3 O 4 /Fe 7 S 8 @C composites. The as-prepared composite shows three-dimensional (3D) interlaced lamellar structure self-assembled by nanoparticles with size of dozens of nanometers. Electrochemical measurements results inferred that the electrode displays better comprehensive electrochemical performance than conventional Fe 3 O 4 @C sample. For example, it delivers a reversible discharge capacity of 819 mAh g -1 at 1 A g -1 after 300 cycles and a capacity retention rate up to 83.6%. This is mainly due to the unique 3D interlaced lamellar structure and the support of carbon skeleton, which inhibits the volume change during lithium storage process. In addition, the presence of sulfide provides additional capacity and promotes the reaction kinetics. In view of the cost-effective feedstock and the convenience of preparation, this study provides an extensible strategy for advanced Fe 3 O 4 anode materials of lithium-ion batteries.