Fabrication of Si–SiO2@Fe/NC composite from industrial waste AlSiFe powders as high stability anodes for lithium ion batteries

Abstract

Industrial waste AlSiFe powders are employed to provide polyporous SiO2 frameworks by alkali etching and Si nanoparticles are embedded in the gaps of the porous SiO2 frameworks via ultrasonic stirring. The nitrogen doped carbon layers are generated on the surface of the porous frameworks to yield the Si–SiO2@Fe/NC composite by polymerization of dopamine and subsequent carbonization process, in which the polyporous SiO2 frameworks can not only relieve huge volume changes of the active Si particles, but also can provide abundant charge transfer channels for electrons and lithium ions. Moreover, the nitrogen doped carbon layers significantly promote the electronic conductivity of the composite. Benefitting from these coordinating effects, the Si–SiO2@Fe/NC anodes demonstrate outstanding cycle performance with a charge specific capacity of 1394.7 mAh g−1 and up to 100% capacity retention rate after 100 cycles under test current of 200 mA g−1, excellent rate performance with a charge specific capacity of 653.1 mAh g−1 under test current of 3000 mA g−1 and enhanced lithium ion diffusion rate of 4.161 E−13 cm2 s−1 in the 100th cycle. As a consequence, the comprehensive fabrication of the Si–SiO2@Fe/NC composite from industrial wastes could provide a promising idea to develop novel anodes for lithium ion batteries.