Alloy negative materials for Li-ion batteries have been focused on because of high specific capacity and safety, which would be a promising material for next generation Li-ion batteries. In this work, alloy film anode has been prepared by depositing SnZn on Cu foil with a magnetron sputtering method, followed by heat-treatment. A Cu3Sn intermetallic composite was formed after the heat-treatment. The SEM result showed that the alloy film was composed of alloy particles with the size of around 5 μm, and the alloy particle was composed of smaller particles with size of around 50 nm. The alloy film anode showed high charge-discharge capacity and columbic efficiency, and good cyclic stability. At potential of 0.01～1.0 V (vs. Li/Li＋), the discharge capacity remained over 300 mAh•g－1 after 200 cycles, and the columbic efficiency was over 98.0%. These results should be attributed to the unique structure of the alloy film anode composed of intermetallic composite, thin film and nano-sized active material.

Key words: Li-ion battery, negative material, magnetron sputtering, tin, film