In-situ encapsulating ultrafine CoFe2O4 nanoparticle into porous N-doped carbon nanofiber membrane as self-standing anode for enhanced lithium storage performance

The ultrasmall CoFe2O4 nanoparticles in situ encapsulated in porous N-doped carbon nanofibers membranes (CFO@PNCFM) with different pore structures have been prepared by electrospinning and subsequent carbonization. When immediately used as self-standing anodes for lithium-ion batteries (LIBs), the optimized CFO@PNCFM exhibits superior lithium storage properties with high rate capability (476.5 mAh g−1 at 2 A g−1) and long stable cycle life (755.8 mAh g−1 at 100 mA g−1 after 200 cycles). The outstanding electrochemical performance may be mainly ascribed to the synergistic effect of special 3D conductive porous carbon nanofibers (PCNFs) network and ultrafine CoFe2O4 nanoparticles in energy storage, which can significantly enhance the utilization efficiency of electroactive materials and improve the charge-transport kinetics. Moreover, the CoFe2O4 nanoparticles bonded closely to PCNFs through strong metal-oxygen bridges, which promote the electron capture and transfer from PCNFs to CoFe2O4, and thus achieving fast electrochemical reaction kinetics. Meanwhile, the porous structure can not only alleviate the volume change during charge/discharge cycles, but also supply numerous active sites for lithium storage, resulting in a high reversible capacity as well as good cycle stability and rate performance.