A Sn–Co–C composite is prepared by mechanochemical synthesis using tin powder and a cobalt–carbon composite through the pyrolysis of Co (III)-acetylacetonate. The composite is studied as an anode material for Li secondary batteries. The reaction mechanism is investigated using various analytical techniques. Although the composite is initially composed of Co3Sn2 as the major phase and CoSn2 as the minor one, the Co3Sn2 transformed into CoSn2 during the second cycle and remained in this form throughout the following cycles. The Sn–Co–C composite shows an excellent capacity retention of 435mAhg−1 over 100 cycles.