Construction of robust coupling interface between MoS2 and nitrogen doped graphene for high performance sodium ion batteries

Abstract

Abstract As a layered inorganic material, MoS2 has recently attracted intensive attention as anode for sodium ion batteries (SIBs). However, this anode is plagued with low electronic conductivity, serious volume expansion and sluggish kinetics, resulting in capacity fading and poor rate performance. Herein, we develop an interface engineering strategy to substantially enhance the sodium storage performance of MoS2 by incorporating layered MoS2 into three dimensional N-doped graphene scaffold. The strong coupling-interface between MoS2 and N-doped graphene scaffold can not only stabilize the MoS2 structure during sodium insertion/extraction processes, but also provide plenty of anchor sites for additional surface sodium storage. The 3D MoS2@N-doped graphene composite as anode for SIBs performs an outstanding specific capacity of 667.3 mA h g−1 at 0.2 A g−1, a prolonged stability with a capacity retention of 94.4% after 140 cycles and excellent rate capability of 445 mA h g−1 even at a high rate of 10 A g−1. We combined experiment and theoretical simulation to further disclose the interaction between MoS2 and N-doped graphene, adsorption and diffusion of sodium on the composite and the corresponding sodium storage mechanism. This study opens a new door to develop high performance SIBs by introducing the interface engineering technique.