High-capacity and amorphous MoS3 decorated hollow Co9S8 nano-spheres composites for boosted sodium ion storage

Herein, the high-capacity and amorphous MoS 3 has been employed to decorate the hollow Co 9 S 8 nano-spheres to fabricate the Co 9 S 8 /MoS 3 composites by a three-step synthesis. The chain-like and amorphous MoS 3 can provide a high capacity of 894 mAh g −1 and generate abundant active sites to boost the sodium storage properties of Co 9 S 8 based electrode. The heterogeneous interface between Co 9 S 8 and MoS 3 is conducive to the promotion of charge transfer and Na + diffusion kinetics. Thus, the Co 9 S 8 /MoS 3 as the novel anode materials exerts more outstanding sodium storage properties than pure Co 9 S 8 . At a given current density of 0.5 A g −1 , the Co 9 S 8 /MoS 3 delivers a desired reversible capacity of 621 mAh g −1 for 90 cycles. Even at 2 A g −1 , the Co 9 S 8 /MoS 3 exhibits a stable cyclic performance, the charge specific capacity is about 518 mAh g −1 for 500 cycles. At a high rate of 5 A g −1 , a high capacity of 486 mAh g −1 can be achieved, which is obviously higher than that of pure Co 9 S 8 . The remarkable sodium storage properties of Co 9 S 8 /MoS 3 are mainly resulted from the cooperate effects of amorphous MoS 3 and hollow Co 9 S 8 nano-spheres, which demonstrate the promising application of Co 9 S 8 /MoS 3 in future sodium storage devices.