One-step fabrication of Fe-Si-O/carbon nanotube composite anode material with excellent high-rate long-term cycling stability

The composite of Fe2SiO4 with carbon nanotubes, Fe3O4 and Fe3C are fabricated by a simple one-step reaction between ferrocene and tetraethyl orthosilicate. The composite utilized as anode material for Li-ion storage exhibits ever-increasing capacities when cycled at a current density of 100 mA g−1, and after 280 cycles, a stable capacity of 588 mAh g−1 is achieved. When cycled at 200, 400, 800 and 1600 mA g−1, the reversible capacities are 364, 323, 281, 235, and 186 mAh g−1, respectively. Even cycled at 500 mA g−1, a reversible capacity of 350 mAh g−1 is retained after 600 cycles. The excellent performance is much superior to that of the carbon-coated Fe3O4 prepared under the similar conditions. The outstanding performance associates significantly with the electronic conductivity of in-situ formed carbon nanotubes with uniform dispersion and Fe3C coated on the Fe2SiO4 nanoparticles, as well as the formation of lithium silicates to act as solid electrolyte for enhancing the ionic conductivity.