Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (06): 1439-1445.doi: 10.3866/PKU.WHXB20110607

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Surfactant Carbonization to Synthesize a Fe3O4/C Composite and Its Electrochemical Performance

CHENG Feng, HUANG Ke-Long, LIU Su-Qin, FANG Xue-Song, ZHANG Xin   

  1. College of Chemistry & Chemical Engineering, Central South University, Changsha 410083, P. R. China
  • Received:2011-03-14 Revised:2011-03-30 Published:2011-05-31
  • Contact: HUANG Ke-Long E-mail:klhuang@mail.csu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (50972165).

Abstract:

Oleic acid-capped α-Fe2O3 nanoparticles were initially prepared as precursors by a simple hydrothermal method. Fe3O4/C nanocomposites were synthesized by annealing the precursor at 500 °C for 1 h under an Ar atmosphere. The surface organic groups and core phase structure of the samples were characterized by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD), respectively. Scanning electron microscopy (SEM) was used to observe their morphology. The existence of carbon was confirmed by elemental analysis, energy-dispersive X-ray (EDX) spectroscopy and high-resolution transmission electron microscopy (HRTEM). Cyclic voltammetry (CV) and galvanostatic discharge/charge measurements were used to evaluate the electrochemical performance of the as-prepared Fe3O4/C nanocomposites. The results showed that Fe3O4/C nanocomposites were spindles alike with a length of about 200 nm and a diameter of about 100 nm. A carbon layer of 1-2 nm in thickness was coated on the surface of the Fe3O4 nanocrystals and the carbon content was 1.956% (mass fraction). As anode materials for lithium-ion batteries, the composite exhibited excellent cycling performance (691.7 mAh·g-1 after 80 cycles at 0.2C (1C=928 mA·g-1)) and rate capability (520 mAh·g-1 after 20 cycles at 2C). Compared with commercial Fe3O4 particles, the remarkably improved electrochemical performance of the Fe3O4/C composites was attributed to in situ carbon coating, which prevented nanoparticle aggregation, increased electronic conductivity and stabilized the solid electrolyte interface (SEI) films.

Key words: Lithium-ion battery, Magnetite, Surfactant carbonization, In situ carbon coating, Composite

MSC2000: 

  • O646