Bimetallic sulfide FeS2@SnS2 as high-performance anodes for sodium-ion batteries

A novel hierarchical structure of bimetal sulfide FeS2@SnS2 with the 1D/2D heterostructure was developed for high-performance sodium-ion batteries (SIBs). The FeS2@SnS2 was synthesized through a hydrothermal reaction and a sulphuration process. The exquisite 1D/2D heterostructure is featured with 2D SnS2 nanoflakes anchoring on the 1D FeS2 nanorod. This well-designed FeS2@SnS2 provides shortened ion diffusion pathway and adequate surface area, which facilitates the Na+ transport and capacitive Na+ storage. Besides, the FeS2@SnS2 integrates the 1D/2D synthetic structural advantages and synthetic hybrid active material. Consequently, the FeS2@SnS2 anode exhibits high initial specific capacity of 765.5 mAh·g−1 at 1 A·g−1 and outstanding reversibility (506.0 mAh·g−1 at 1 A·g−1 after 200 cycles, 262.5 mAh·g−1 at 5 A·g−1 after 1400 cycles). Moreover, the kinetic analysis reveals that the FeS2@SnS2 anode displays significant capacitive behavior which boosts the rate capacity.