N-doped carbon matrix supported Fe3Ni6S8 hierarchical architecture with excellent sodium storage capability and electrocatalytic properties

Due to rich redox sites and high electronic conductivity, multi-metal sulfides are considered as a competitive candidate for energy storage and conversion. Recently, nanostructure engineering and composition control are usually employed to enhance the electrochemical performance of metal sulfides. Herein, Fe3Ni6S8 solid solution anchored on N-doped carbon matrix (denoted as Fe3Ni6S8/N-C) with hierarchical structure is constructed through a facile freeze-drying/carbonization method using NaCl template. Fe3Ni6S8/N-C hybrid consists of interconnected porous carbon networks and nanoflakes can act as robust anode for sodium ion batteries (SIBs) and considerable electrocatalysts for hydrogen evolution reaction (HER). It delivers high capacity of 450.1 mAh g(-1) at 10 A g(-1), giving high capacity retention of 68.7% compared to that at 0.1 A g(-1). And stable capacities of 596.6 mAh g(-1) can be maintained for 180 cycles at 1.0 A g(-1) as SIBs anode. When used as a HER catalyst, it exhibits a smaller Tafel slope of 55 mV dec(-1) and superior long-term stability. The Fe3Ni6S8/N-C hierarchical structure can provide enhanced conductivity, rich active sites and rapid electron/ion transport channels, leading to impressive electrochemical performance. (C) 2019 Elsevier Ltd. All rights reserved.