Carbon nanofiber (CNF) supported cobalt oxide composites as high-capacity anode materials were prepared through a facile, effective method for potential use in rechargeable lithium-ion batteries. The effects of the calcining temperature on the crystallinity,grain size, specific surface area of Co3O4 and phase transformation from Co3O4 to CoO were studied in detail. Both the specific surface area and CNF content in CNF-cobalt oxide composites strongly affect the electrochemical performance of these series composites. The CNF-Co3O4 composite with 24.3% CNF pyrolyzed at 500 degrees C in At shows all excellent cycling performance, retaining a specific capacity of 881 mAh g(-1) beyond 100 cycles. Homogeneous deposition and distribution of nanosized Co3O4 particles on the surface of CNF can stabilize the electronic and ionic conductivity as well as the morphology of Co3O4 phase, which may be the main reason for the markedly improved electrochemical performance. (c) 2008 Elsevier Ltd. All rights reserved.