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

Abstract

Herein, the high-capacity and amorphous MoS3 has been employed to decorate the hollow Co9S8 nano-spheres to fabricate the Co9S8/MoS3 composites by a three-step synthesis. The chain-like and amorphous MoS3 can provide a high capacity of 894 mAh g−1 and generate abundant active sites to boost the sodium storage properties of Co9S8 based electrode. The heterogeneous interface between Co9S8 and MoS3 is conducive to the promotion of charge transfer and Na+ diffusion kinetics. Thus, the Co9S8/MoS3 as the novel anode materials exerts more outstanding sodium storage properties than pure Co9S8. At a given current density of 0.5 A g−1, the Co9S8/MoS3 delivers a desired reversible capacity of 621 mAh g−1 for 90 cycles. Even at 2 A g−1, the Co9S8/MoS3 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 Co9S8. The remarkable sodium storage properties of Co9S8/MoS3 are mainly resulted from the cooperate effects of amorphous MoS3 and hollow Co9S8 nano-spheres, which demonstrate the promising application of Co9S8/MoS3 in future sodium storage devices.