LAUSR

Abstract Kapok fibres were used as micro-tube biotemplate and bio-carbon source to synthesise Fe 3 O 4 /C composites, which were then utilised as anode materials. Fe 3 O 4 nanoparticles were grown uniformly onto the external surface and internal channel of kapok carbon fibres. The flexibility, high specific surface area and electronic conduction of kapok fibres can buffer the volume expansion as well as inhibit the aggregation of Fe 3 O 4 nanoparticles. Thus, the electrical integrity and structural of the Fe 3 O 4 /C composites electrode during lithiation/delithiation processes. The Fe 3 O 4 /C composites electrode delivers a high reversible capacity of 596 mA h g −1 after 100 cycles and an ultra-high coulombic efficiency approaching 100%. The high electrochemical performance of the Fe 3 O 4 /C composites can be caused by the synergistic effect of the Fe 3 O 4 nanoparticles and the structure of kapok carbon fibres.