The multicomponent nanocomposites of FeSi2@Si@graphene and FeSi2@Si are synthesized via the magnesiothermic reduction of core-shell Fe3O4@SiO2 nanoparticles with/without graphene oxide shell. In the course of the magnesiothermic reaction, the SiO2 and Fe3O4 components in the Fe3O4@SiO2 core-shell particles are transformed into elemental Si and FeSi2, respectively. The formation of intimately-coupled composite structure consisting of Si and FeSi2 domains as well as the coating of graphene layer is verified by high resolution-transmission electron microscopy. Both the nanocomposites of FeSi2@Si@graphene and FeSi2@Si show promising anode performance for lithium ion batteries, indicating a beneficial role of the electrochemically inactive FeSi2 domains in alleviating the drastic expansion/contraction of elemental Si during the electrochemical cycling. The better cyclability and rate characteristic are obtained for the FeSi 2@Si@graphene nanocomposite than for the graphene-free FeSi 2@Si one, which is attributable to the depression of pulverization and the enhancement of electrical conductivity upon the coating of graphene layer. The present work highlights that the magnesiothermic reaction provides a powerful synthetic route to multicomponent Si-based nanocomposites with tailored composition and complex geometry.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korean Government (MEST)" (NRF-2010-C1AAA001-2010-0029065), by the Core Technology of Materials Research and Development Program of the Korea Ministry of Intelligence and Economy (grant No. 10041232), by the National Research Foundation of Korea(NRF) grant funded by the Korea government (MEST) (NRF-20011-001419), and by the National Research Foundation of Korea (NRF) Grant funded by the Korean Government (MEST)" (NRF-2011-0014219).
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)