The CoS2/NiS2-RGO composite with excellent electrochemical performance is first used as an anode material for sodium-ion capacitors (SICs) and sodium-ion batteries (SIBs). CoS2/NiS2-RGO is prepared by one-step hydrothermal process. In half-cell tests, CoS2/NiS2-RGO exhibits a remarkably high reversible capacity of 473.7 mA h g−1 after 50 cycles at the specific current of 100 mA g−1. SICs show an impressive energy density of 139.1 W h kg−1 at the power density of 14,000 W kg−1, which has great advantages compare to the commercial lithium ion batteries. SIBs also show a good capacity of 50 mA h g−1 at a rate of 5 °C. The excellent electrochemical performance of CoS2/NiS2-RGO is mainly attributed to the heterostructure formed by CoS2 and NiS2, which effectively improves the electrical conductivity. On the other hand, there is a good synergistic effect between RGO and CoS2/NiS2. The large specific surface area of RGO makes CoS2/NiS2 disperse uniformly on the surface of RGO, preventing agglomeration and reducing particle size of CoS2/NiS2. In turn, CoS2/NiS2 acting on the surface layer of RGO hinders the secondary overlap and increases the electrical conductivity of RGO. The mixed bimetallic sulfide/RGO system is expected to promote the rapid development of sodium storage devices. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.