MOF derived NiS/ZnS heterostructure enhancing the electrochemical kinetics for sodium ion batteries

Metal sulfides has attracted numerous attentions as the anode material for sodium ion batteries (SIBs) because of their excellent theoretical capacities. However, these materials still suffer from poor electrochemical performance caused by the volume expansion and sluggish electrochemical kinetics. In this work, the NiS/ZnS embedded in carbon material with heterogeneous interface is fabricated through a sulphurization process using metal organic framework (MOF) as precursor followed by acid treatment (NiS/ZnS@C-AT). It is found that the generated abundant heterogeneous interface in the present materials effectively promotes the electronic conductivity and Na⁺ diffusion, which enhances the electrochemical kinetics, causing good rate performance. Moreover, the carbon material produced by the sulphurization process with high temperature can increase the structural stability of the NiS/ZnS material during charging/discharging process, resulting in long cycling stability. As a result, the NiS/ZnS@C-AT based anode for SIBs exhibits an excellent reversible capacity of 456.8 mA h g⁻¹@ 0. 1 A g⁻¹, good cycling stability with 404.5 mA h g⁻¹@2 A g⁻¹ after 1900 cycles, and superior rate performance with 381.3 mA h g⁻¹@5 A g⁻¹.