High-Temperature Stable and Long-Life FeS@Hollow Carbon Composite as Anode Material for High-Performance Sodium-Ion Batteries

Abstract

Sodium-ion batteries (SIBs) are a promising alternative to lithium-ion batteries due to their cost-effectiveness and abundant sodium resources. However, their electrochemical performance is limited by the larger ionic radius and severe volume expansion of Na+ ions. In this study, hollow yolk-shell structured iron sulfide (FeS) was encapsulated in graphitized carbon (H-C@FeS) to address these challenges. The material was synthesized using a solvothermal technique, followed by SiO2 templating, carbon coating, and thermal treatment. The hollow structure buffered volume changes, while the carbon shell enhanced conductivity and structural stability. H-C@FeS exhibited excellent electrochemical performance, delivering 450 and 350 mAhg−1 at 1.0 and 5.0 Ag−1, respectively, with high-capacity retention. Moreover, the electrode maintained stable capacities of 600 mAhg−1 at 60°C, indicating superior high-temperature stability. Electrochemical analyses, including CV, GITT, and in situ EIS with DRT interpretation, confirmed enhanced Na+ diffusion kinetics. The results suggest H-C@FeS as a promising high-performance and thermally stable anode for next-generation SIBs. (Figure presented.).