▎ 摘　　要

Sodium ion battery (SIB) is a promising power storage system for sustainable energy storage and conversion (ESC) due to the abundant worldwide Na resources and its much lower cost. In this paper, the electrochemical performance of Na+ intercalation/extraction in nitrogen-doped graphene nanosheets (N-GNS) were studied. The experimental results showed that the N-GNS exhibited high Na+ storage capacity (260 mA h g(-1) at 50 mA g(-1)), good rate capability and excellent cycle performance even at a very high current density (90 mA h g(-1) at 500 mA g(-1) for 600 cycles). The superior electrochemical performance of N-GNS is due to the N-doping-induced defects structure, which makes the N-GNS suitable for the fast diffusion of the relatively large-sized Na-' with low ion-transport resistance and effective storage of Na+ during discharge-charge processes. (C) 2016 Elsevier B.V. All rights reserved.