Surface porous carbon nanofibers based on coaxial electrospinning with improved mechanical strength and cycle stability for freestanding anode in Li-ion batteries

Porous carbon nanofibers (PCNFs), are widely used as free-standing anode materials for lithium-ion batteries (LIBs), due to their high specific surface area and excellent ion diffusion kinetics, but they also present problems of reduced rate performance and cycling performance, due to poor strength caused by porosity. Herein, a novel surface porous carbon nanofiber (SPCNFs) is prepared by coaxial electrospinning, followed by carbonization. All the pores are distributed in the shell of the fibers, with a dense amorphous carbon structure in the core, which would not only provide abundant lithium-ion embedding sites, and accelerate the penetration of electrolyte ions, but also alleviate the reduction of mechanical properties (with a similar to 30% improvement to PCNFs). Consequently, our LIBs assembled with this SPCNFs anode represent remarkable cycling stability (445.33 mAh g(-1) at 100 mA g(-1) after 100 cycles and 388.92 mAh g(-1) at 1 A g(-1) after 1000 cycles), and excellent rate capacity (317.55 mAh g(-1) at 1 A g(-1)).