锂离子电池中高容量Si-Cu/C复合负极材料的制备与性能研究

Preparation and Characterization of High Capacity Si-Cu/C Composites as Anode Materials for Lithium-Ion Battery Anodes

采用高能球磨方法制备了用作锂离子电池负极材料的Si-Cu/C复合材料。X射线衍射和扫描电子显微镜结果表明,复合材料中Si和Cu5Si是共存的,活性硅颗粒均匀地分散在石墨和惰性的铜硅合金基体中。电化学测试在电流密度0.2 mA.cm-2,电压范围0-1.4 V条件下进行,其结果表明高分散Si-Cu/C复合材料首次可逆容量为524 mAh.g-1,远高于目前普遍使用的中间相碳微球;循环寿命也远优于同粒度的硅单体,经过30次循环后容量仍保持531 mAh.g-1。其高比容量和良好的循环性能表明:高分散Si-Cu/C复合材料有望替代碳成为锂离子电池负极材料。

Si-Cu/C composites were prepared by highenergy ball-milling for anode materials of lithium-ion batteries. Scanning electron microscopy （ SEM ） and X-ray diffraction （XRD） results indicate that the active Si particles distribute uniformly in the matrix of the Si-Cu alloys and graphite. The composites demonstrate an initial reversible capacity of 524 mAh·g^-1 at current densities of 0.2 mA· cm^-2 with voltage cut-off of 0 V/1. 4 V, and the capacity retains at 551 mAh·g^-1 after 30 cycles, a larger reversible capacity than commercialized graphite and better cyclic performance than silicon. The large reversible capacity and good cycle prove to be based anode ability suggest that the composites may an alternative to conventional graphitematerials for lithium-ion batteries.