FeO/C anode materials of high capacity and cycle stability for lithium-ion batteries synthesized by carbothermal reduction

FeO/C composites are synthesized by carbothermally reducing ball-milled mixtures of nano-sized Fe2O3 and acetylene black (AB) in different ratios. The structure evolution of the mixtures during carbothermal reduction and the electrochemical properties of the reduced products as anode materials for lithium-ion batteries have been investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and electrochemical testing. The results show that Fe2O3 is reduced to FeO by AB at 800 degrees C. The FeO particles inherit the nano-size feature of the Fe2O3 particles and well disperse in the composites. The FeO/C composites possess capacity retentions higher than 96% after 50 cycles when the AB additions reach 50 wt.%. The FeO/C composite with 50 wt.% AB addition shows a superior capacity of 510 mA h/g after 50 cycles, which is much higher than that of the Fe2O3/50 wt.% AB mixture, which is 400 mA h/g. The flexible structure and high electronic conductivity of AB, the comparatively high electronic conductivity of FeO all play effective roles in improving the electrochemical properties of the FeO/C composites. 50 wt.% is a recommended content for the addition of AB. Too high content of AB lowers the capacity of the FeO/C composites due to the low capacity nature of AB. The synthesis method is considerably facile for large-scale production. (C) 2013 Elsevier B.V. All rights reserved.