锂离子电池用SnZn/Cu薄膜负极材料的研究

SnZn/Cu Film Anode for Lithium-ion Batteries

合金型锂离子电池负极材料由于容量高、安全性好而备受关注.采用磁控溅射法在铜箔上渡膜制备锡锌薄膜,经热处理后得到合金薄膜电极.薄膜热处理后,表面活性层形成Cu3Sn中间合金.合金薄膜是由尺寸在5μm左右的合金颗粒构成,而合金颗粒则由更小的尺寸在50nm左右微粒组成,该合金薄膜同时具有薄膜、中间合金和纳米结构材料的特征.合金薄膜电极具有较高的充放电容量、良好的循环性能和非常高的充放电效率.在0.01～1.0V(vs.Li/Li+)区间,电极循环200周后放电容量保持在300mAh·g-1以上,与第一次脱锂容量相比较,容量保持率高达91.9%,充放电效率大于98.0%.

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 ~tm, 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.