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 Co 3 Sn 2 as the major phase and CoSn 2 as the minor one, the Co 3 Sn 2 transformed into CoSn 2 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.