New Synthesis of a Foamlike Fe₃O₄/C Composite via a Self-Expanding Process and Its Electrochemical Performance as Anode Material for Lithium-Ion Batteries

A novel foamlike Fe3O4/C composite is prepared via a sol-gel type method with gelatin as the carbon source and ferric nitrate as the iron source, following a postannealing treatment. Its lithium storage properties as anode material for a lithium-ion battery are thoroughly investigated in this work. With the interaction between ferric nitrate and gelatin, the foamlike architecture is attained through a unique self-expanding process. The Fe3O4/C composite possesses abundant porous structure along with highly dispersed Fe3O4 nanocrystal embedment in the carbon matrix. In the constructed architecture, the 3D porous network property ensures electrolyte accessibility; meanwhile, nanosized Fe3O4 promotes lithiation/delithiation, owing to numerous active sites, large electrolyte contact area, and a short lithium ion diffusion path. As a result, this Fe3O4/C composite electrode demonstrates an excellent cycling stability with a reversible capacity of 1008 mA h g(-1) over 400 cycles at 0.2C (1C = 1000 mA g(-1)), as well as a superior rate performance with reversible capacity of 660 and 580 mA h g(-1) at 3C and 5C, respectively.