简单温和的置换途径制备锂离子电池纳米硅负极材料

Facile preparation of nanoscale silicon as anode materials for lithium ion batteries by a mild temperature metathesis route

硅被认为是一种很有前景的锂离子电池负极材料,因为它理论比容量高达3580 mAh/g(Li_(3.75)Si,室温下形成)。分别以四氯化硅和锌粉作为硅源与还原剂,通过简单有效的置换反应在500℃的条件下制备出了纳米级硅,该方法制备工艺简单,并且原料成本低廉。所得到的纳米级硅颗粒为150~200 nm的球状,并对其进行电化学性能测试,该材料在0.2 A/g的电流密度下首次脱锂比容量能够达到1 747.7 mAh/g。然后以蔗糖为碳源通过高温热解法合成了硅碳复合材料,其50次循环后的脱锂容量保持率为82%。

Silicon was regarded as one of the promising alternative anode materials for next-generation lithium ion batteries （LIBs） due to its high theoretical specific capacity of 3580 mAh·g^–1 （Li3.75Si formed at room temperature）. In this work, nanoscale silicon was synthesized via a simple and effective metathesis reaction, in which SiCl4 served as the silicon source and Zn as the reductant, respectively, at a mild temperature of 500 ℃. This method for producing nanoscale silicon is simple, facile and low-cost. The as-prepared silicon particles are spherical with a diameter of 150-200 nm and the delithiation specific capacity can attain as high as 1 747.7 mAh g^–1 at a current density of 0.2 A·g^–1. Furthermore, Si/C composites are synthesized via a high temperature pyrolytic method with sucrose as the delithiation precursor and the capacity retention is 82.0% after 50 cycles.