Nickel sulfide nanoparticle anchored reduced graphene oxide with improved lithium storage properties

Abstract Reduced graphene oxide@nickel sulfide (NiS) composites are synthesized by a solvothermal method. Uniformly dispersed NiS nanoparticles with a size of 15∼25 nm are embedded to the surface of a three-dimensional (3D) reduced graphene oxide. The favorable 3D-framework with a large amount of pores has been characterized systematically. As a Li-ion battery anode, the reduced graphene oxide@NiS anode keeps a reversible capacity of 1328.7 mAh g-1 at 0.1 A g-1 after 120 cycles. Meanwhile, it shows an enhanced rate capability of 673.6 mAh g-1 at 1.0 A g-1. The enhanced reversible capacity and cycling stability is ascribed to the reduced graphene oxide and its unique 3D porous nanostructure. Furthermore, the existence of C‒S bonds make reduced graphene oxide and nickel sulfide in the composite combine better during the cycling process, and enhance their synergistic effect. Since that, the conductivity, volume-variation and active sites of the composites are greatly improved.