Interfacial Electronic Modulation and Carbon Confinement of MoS2/FeS2 Heterostructure Derived from Mechanochemical Reaction for Enhanced Sodium Storage Properties

Abstract

Molybdenum disulfide (MoS2) is a promising anode material for sodium-ion batteries (SIBs) due to its layered structure and high theoretical specific capacity. However, it faces challenges such as low electronic conductivity, severe volume changes, and insufficient Na+ transport behaviors. Herein, a MoS2/FeS2 heterostructure confined in a three-dimensional conductive carbon framework (MoS2/FeS2/C) is constructed via a mechanochemical ball-milling method, followed by a one-step sulfurization process. The room-temperature mechanochemical reaction yields a Mo- and Fe-containing amorphous precursor, while the subsequent sulfurization facilitates the in situ formation of intimately coupled heterointerfaces of MoS2/FeS2. Comprehensive structural and electronic analyses reveal interfacial charge redistribution and local coordination reconstruction, which accelerate charge transfer and lower the Na+ diffusion barrier. Meanwhile, the carbon framework effectively buffers volume variations during repeated cycling. The resulting MoS2/FeS2/C anode delivers a high reversible capacity of 793 mAh g−1 at 1 A g−1, outstanding rate capability (522 mAh g−1 at 5 A g−1) and long-term cycling stability (575 mAh g−1 at 5 A g−1 over 1500 cycles). This work presents a mechanochemical reaction-guided interface architecture strategy for constructing sulfide heterostructures with enhanced sodium storage properties, emphasizing the significance of crystal interface design in advanced battery materials.