Construction of hierarchical ZnS/MoS2 bimetallic sulfides heterostructures for high – performance sodium ion batteries

The rational design and construction of bimetallic hierarchical nanostructures are effective strategies for the development of conversion alloying reaction anode for sodium ion batteries (SIBs). Herein, novel hierarchical ZnS/MoS2 bimetallic sulfides are designed and fabricated via a simple sulfuration process, in which ZnS/MoS2 nanoparticles are encapsulated in Zn/Mo bimetallic imidazolate framework (Zn/Mo BIFs) derived nitrogen doped carbon frameworks with covering reduced graphene oxide (ZnS@MoS2/NC@rGO). The derived nitrogen doped carbon and graphene nanosheets can enhance electrical conductivity, and accommodate volume changes of ZnS/MoS2 on the cycling. Meanwhile, the ZnS-MoS2 heterostructure accelerates diffusion dynamics in the interface, and promotes the charge transfer rate. Due to the compositional and structural features, the obtained ZnS@MoS2/NC@rGO sample delivers superior sodium storage performance, which achieves a specific capacity of 480 mAh/g at 0.2 A/g over 100 cycles, and good rate capability of 308 mAh/g at 4 A/g. The full SIBs are fabricated by ZnS@MoS2/NC@rGO anode with homemade Na3V2(PO4)3/C cathode which exhibit the high energy density of 127.8 Wh kg−1 at the power density of 105.9 W kg−1. The preparation strategy manifests an effective and simple method to in situ fabricate hierarchical hetero-interfaces bimetallic sulfides/carbon anode materials for SIBs.