In Situ Hybridization Strategy Constructs Heterogeneous Interfaces to Form Electronically Modulated MoS/FeS as the Anode for High-Performance Lithium-Ion Storage.

The interfacial effect is important for anodes of transition metal dichalcogenides (TMDs) to achieve superior lithium-ion storage performance. In this paper, a MoS/FeS heterojunction is synthesized by a simple hydrothermal reaction to construct the interface effect, and the heterostructure introduces an inherent electric field that accelerates the de-embedding process of lithium ions, improves the electron transfer capability, and effectively mitigates volume expansion. XPS analysis confirms evident chemical interaction between MoS and FeS via an interfacial covalent bond (Mo-S-Fe). This MoS/FeS anode shows a distinct interfacial effect for efficient interatomic electron migration. The electrochemical performance demonstrated that the discharge capacity can reach up to 1217.8 mA h g at 0.1 A g after 200 cycles, with a capacity retention rate of 72.9%. After 2000 cycles, the capacity retention is about 61.6% at 1.0 A g, and the discharge capacity can still reach 638.9 mA h g. Electrochemical kinetic analysis indicated an enhanced pseudocapacitance contribution and that the MoS/FeS had sufficient adsorption of lithium ions. This paper therefore argues that this interfacial engineering is an effective solution for designing sulfide-based anodes with good electrochemical properties.