Metal-organic framework derived FeS/MoS2 composite as a high performance anode for sodium-ion batteries

Abstract Considering the superior performances of MOF-based and MoS2-based materials, a flower-like FeS/MoS2 composite is synthetized using MIL-100(Fe) as a precursor. Electronic density of states and band structure are simulated by density functional theory (DFT) calculations, which prove that FeS/MoS2 heterostructure exhibits metallic behavior. Unique structure and powerful hetero-interface synergistic effect of FeS/MoS2 is conducive to improve the stability of sodium-ion batteries (SIBs). It provides reversible capacities of 464 and 365 mA h g−1 at 0.1 and 1.0 A g−1. When the current density increases to 5 A g−1, FeS/MoS2 delivers a high capacity of 325 mA h g−1 with a capacity retention rate (71.1%). Moreover, it can maintain a stable specific capacity of 331 mA h g−1 at 2.0 A g−1 after 200 cycles. Adsorption energy calculated by DFT indicates that more Na atoms may be trapped on the top of Mo atom between FeS and MoS2 layers. This study may stimulate the interesting of multivariate-MOFs/ covalent organic frameworks (COFs) composite emerging two-dimensional materials and facilitate the application of composite electrode in high-performance SIBs.