Flexible Fe3O4/PCNFs membrane prepared by an innovative method as high-performance anode for lithium-ion battery

Abstract Porous carbon nanofibers (PCNFs) of anchoring abundant oxygen-containing groups are prepared by simply calcining carbon nanofibers (CNFs) in air. And then the Fe(OH)3 nanoparticles with positive charges in aqueous solution can anchor on the surface of PCNFs by the mutual electrostatic force. Ultimately, Fe3O4/PCNFs nanocomposite is fabricated by subsequent hydrothermal reaction. The Fe3O4/PCNFs composite exhibit a high reversible capacity of 668.5 ​mA ​h ​g−1 at a current density of 0.5 ​A ​g−1 after 150 cycles, which has an improved capacity over the sum of that of single PCNFs (316.7 ​mA ​h ​g−1) and Fe3O4 nanoparticles (146.8 ​mA ​h ​g−1). On one hand, the abundant pores of PCNFs are beneficial to the transmission and diffusion of lithium-ions. On the other hand, PCNFs as a high conductive framework provide for high-speed electronic transmission. What's more, PCNFs can buffer the volume changes of Fe3O4 nanoparticles. In brief, the preparation method of anchoring oxygen-containing groups onto CNFs is simple but innovative, which avoids the use of strong corrosive acid or strong oxidant, and has been proved for the first time that the PCNFs can load abundant Fe3O4 nanoparticles and the electrochemical performance of Fe3O4/PCNFs is comparable with many other iron oxides/CNFs hybrids.