The complementary use of X-ray diffraction and Sn-119 Mossbauer spectroscopy untangled the cobalt-tin phase's distribution in various Sn-Co-C composites. The composite materials were prepared by a single-step procedure based on low-cost reagents and featuring good scalability was employed. The fluidized state of the Fuel Oil Pyrolysis (FOP) carbon precursor during the copyrolysis reaction produced finely dispersed intermetallic phases embedded in the carbon matrix. The electrochemical performance was correlated to the metal composition and cell impedance after a number of cycles. Cycled electrodes analyzed by X-ray diffraction and Sn-119 Mossbauer spectroscopy revealed that the increased contribution of electrochemically inactive CO3SnC0.7 may explain the observed capacity fading in those samples with high cobalt content. (C) 2013 Elsevier B.V. All rights reserved.