Boosting Sodium Storage of Fe_1-xS/MoS₂ Composite via Heterointerface Engineering

Improving the cycling stability of metal sulfide-based anode materials at high rate is of great significance for advanced sodium ion batteries. However, the sluggish reaction kinetics is a big obstacle for the development of high-performance sodium storage electrodes. Herein, we have rationally engineered the heterointerface by designing the Fe_1-xS/MoS₂ heterostructure with abundant "ion reservoir" to endow the electrode with excellent cycling stability and rate capability, which is proved by a series of in and ex situ electrochemical investigations. Density functional theory calculations further reveal that the heterointerface greatly decreases sodium ion diffusion barrier and facilitates charge-transfer kinetics. Our present findings not only provide a deep analysis on the correlation between the structure and performance, but also draw inspiration for rational heterointerface engineering toward the next-generation high-performance energy storage devices.