基于 ZIF-8 的三维网络硅碳复合材料锂离子电池性能研究

Lithium-ion batteries (LIBs) are widely applied to various portable electronic devices and new energy vehicles. However, the traditional graphite anode with low theoretical capacity (372 mAh/g) is unable to meet the need of the rapid development of economy and society. Herein, a zinc-based metallic organic framework (ZIF-8) derived three-dimensional network carbon coated silicon (Si@NC) composite was designed for lithium-ion battery. Firstly, the surface of nano-silicon was chemical modified; secondly, small size ZIF-8 was in situ grown on the silicon surface to form Si@ZIF-8; finally, the three-dimensional network Si@NC composite was obtained by carbonization. Results show that the three-dimensional network porous structure of the Si@NC composite not only limits the volume expansion of silicon, but greatly improves the conductivity of the materials, exhibiting excellent cycle stability and outstanding rate performance. As a result, a discharge specific capacity of 760 mAh/g is maintained at a high current density of 5 A/g. Using commercial material as cathode and Si@NC as anode, the assembled full LIBs demonstrate a capacity retention of 60.4% at 0.4C (1C =160 mA/g) for 50 cycles. These results indicate that the as-synthesized three-dimensional network porous structure of Si@NC composite has a potential practical application for LIBs.