Nitrogen-doped carbon nanofibers as anode material for high-capacity and binder-free lithium ion battery

•The N-doped CNFs exhibits natural coral-like nanostructure.•The electrode directly works without any binder and conductive additive.•N-doped CNFs anode shows the higher specific capacity and the better rate capability.•N-doping was in situ carried out via thermal decomposition of N-rich imidazole.

Coral-like nitrogen-doped carbon nanofibers (CNFs) were directly grown onto stainless steel by a thermal CVD with N-rich imidazole and acetylene as precursor gasses. The resultant samples, as anodes without using any conductive additive and binder, were assembled into lithium ion batteries. The representative anode exhibits a high reversible capacity of 862.2 mA h g−1 at a current density of 200 mA g−1 and a capacity as high as 415.0 mA h g−1 at 2000 mA g−1 after 150 cycles. Such a superior electrochemical performance can be attributed to the unique coral-like nanostructure of CNFs as a result of nitrogen doping, which could shorten the diffusion distance of Li+ and largen the contact area between the active materials and electrolyte.