FeS under wrinkled thin-layer carbon derived from ionic liquid as a high-performance sodium-ion battery anode material

FeS is a promising anode material with high theoretical capacity in sodium-ion batteries (SIBs). Unfortunately, the unstable structure and poor conductivity of FeS limit its commercial applications. Herein, FeS coated by wrinkled thin layers of carbon (FeS/C) is synthesized by using a simple pyrolysis strategy. The wrinkled carbon layers, which derived from ionic liquids, effectively improve the conductivity and structural stability of FeS. When employed as anode in SIBs, FeS/C exhibits high capacity, long cycle life, and excellent stability. Specifically, when the current density is 0.1 A g⁻¹ and 0.5 A g⁻¹, the reversible capacity of FeS/C reaches 404.7 mAh g⁻¹ and 304.8 mAh g⁻¹ after 100 cycles. When the current density increases to 4 A g⁻¹, the sodium storage can maintain a capacity of 178.8 mAh g⁻¹ after 1000 cycles. The excellent electrochemical performance can be attributed to the wrinkled carbon layers that enhance the structural stability and charge mobility.