Strongly coupled 1D sandwich-like C@Fe3O4@C coaxial nanotubes with ultrastable and high capacity for lithium-ion batteries

Abstract

Sandwich-like carbon/metal oxide hybrids are expected to achieve some strong synergetic effects besides all the desired functions of each constituent and exhibit excellent lithium ion storage properties. In this work, strongly coupled 1D sandwich-like C@Fe₃O₄@C coaxial nanotubes with high surface area are fabricated through a novel and scalable bottom-up synthesis strategy. In the rationally constructed architecture, the inner and outmost carbon layers are capable of not only enhancing the electronic/ionic conductivity of Fe₃O₄ but also protecting encapsulated Fe₃O₄ nanoparticles from being exposed directly to the electrolyte, leading to structural and interfacial stabilization of the Fe₃O₄ interlayer. In consequence, the C@Fe₃O₄@C nanotubes deliver a high reversible capacity of 900 mA h g⁻¹ at 100 mA g⁻¹, excellent rate capacity (650 mA h g⁻¹ at 1000 mA g⁻¹), and a prolonged cycling life (maintaining 1087 mA h g⁻¹ for 150 cycles) for lithium ion batteries (LIBs), which are much better than those of Fe₃O₄ nanotubes and core–shell C@Fe₃O₄ nanotubes.