Facile Fabrication of Honeycomb-like Carbon Network-Encapsulated Fe/Fe₃C/Fe₃O₄ with Enhanced Li-Storage Performance

Abstract

Three-dimensional honeycomb-like carbon network-encapsulated Fe/Fe₃C/Fe₃O₄ composites are constructed via a facile pyrolysis of ferrite nitrate-poly(vinyl pyrrolidone) precursors. The nanostructures of the composites form in terms of the iron catalysis in the pyrolysis process, which greatly depends on the reaction temperature and contents of raw materials. The Fe/Fe₃C/Fe₃O₄/C composite obtained at 700 °C possesses a high surface area, outstanding structural stability, and fast electron/Li ion transportability. As the anode for lithium-ion batteries, it displays a high specific capacity (1295 mAh g^-1 at 0.2 A g^-1), long cycling stability, and fast kinetics (345 mAh g^-1 after 500 cycles at 5 A g^-1). Besides the nanostructures, the marriage of different components also contributes to the superior electrochemical performance. The integral carbon matrix supplies a fast electron/Li transportation pathway. Fe/Fe₃C acts as an electrocatalyst in the electrode, which may bring extra capacity. The satisfied performance and facile fabrication with low cost make it a competitive material in practical applications.