SnS2/Co3S4 Hollow Nanocubes Anchored on S-Doped Graphene for Ultrafast and Stable Na-Ion Storage

SnS2 has been widely studied as an anode material for sodium-ion batteries (SIBs) based on the high theoretical capacity and layered structure. Unfortunately, rapid capacity decay associated with volume variation during cycling limits practical application. Herein, SnS2/Co3S4 hollow nanocubes anchored on S-doped graphene are synthesized for the first time via coprecipitation and hydrothermal methods. When applied as the anode for SIBs, the sample delivers a distinguished charge specific capacity of 1141.8 mAh g(-1) and there is no significant capacity decay (0.1 A g(-1) for 50 cycles). When the rate is increased to 0.5 A g(-1), it presents 845.7 mAh g(-1) after cycling 100 times. Furthermore, the composite also exhibits an ultrafast sodium storage capability where 392.9 mAh g(-1) can be obtained at 10 A g(-1) and the charging time is less than 3 min. The outstanding electrochemical properties can be ascribed to the enhancement of conductivity for the addition of S-doped graphene and the existence of p-n junctions in the SnS2/Co3S4 heterostructure. Moreover, the presence of mesopores between nanosheets can alleviate volume expansion during cycling as well as being beneficial for the migration of Na+.