One-dimensional ZnSe@N-doped carbon nanofibers with simple electrospinning route for superior Na/K-ion storage

Abstract

One-dimensional carbon nanofibers are widely applied as anode material in the energy storage field due to its unique structure and high conductivity. In this work, one-dimensional ZnSe@N-doped carbon nanofibers (ZnSe@NC NFs) are successfully synthesized by electrospinning and annealed without extra troublesome conditions. ZnSe nanocrystals are enfolded in the N-doped carbon nanofibers, which can act as a protective layer to avoid the volume expansion of active material and promote ion transport during the cycling process. More importantly, the as-synthesized ZnSe@NC NFs are served as the anode material and display the admirable storage properties for Na/K-ion batteries. The one-dimensional ZnSe@NC NFs material shows the high capacity of 237 mAh/g for Na-ion batteries at a current density of 1 A/g for 2000 cycles. Meanwhile, it also delivers a high discharge capacity of 337 mAh/g for K-ion batteries at 0.2 A/g for 300 cycles. Additionally, it is confirmed that the pseudocapacitive contribution of the nano-structure material is up to 54.5% at a scan rate of 0.6 mV/s through the cyclic voltammetry (CV) measurement in K-ion batteries.