Ultrafine Li4Ti5O12/C composite is synthesized by microemulsion with oleic acid as carbon precursor and particle size controller. The as-prepared sample is characterized with X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), thermogravimetry analysis (TGA) and nitrogen absorption-desorption isotherms, and its performance as anode of lithium ion battery is determined with charge discharge test and electrochemical impedance spectroscopy (EIS). The characterizations show that the as-prepared sample is composed of ultrafine Li4Ti5O12 particles with average size of 25 nm, which are uniformly dispersed in carbon matrix with a carbon content as low as 2.69 wt%. Charge discharge test indicates that the as-prepared sample exhibits excellent rate performance and cycling stability. At 10C, the highest discharge capacity reaches 1363 mAh g(-1) and the capacity retention is 96.4% after 100 cycles. The improved performance of the Li4Ti5O12/C composite is attributed to the ultrafine particle size and the uniform composite of Li4Ti5O12 with carbon. (C) 2013 Elsevier B.V. All rights reserved.