Self‐assembled 3D NiCo ₂ S ₄ nanotubes‐graphene aerogel composites as an excellent anode for Li‐ion batteries

Abstract

Three-dimensional nickel cobalt sulphide (NiCo 2 S 4) nanotubes-graphene aerogel composites (NGAs) are firstly assembled by an electrostatic interaction between the diallyldimethylammonium chloride-modified NiCo 2 S 4 nanotubes and graphene oxide (GO) sheets, followed by a steerable hydrothermal and freeze-drying process. The final samples are characterised by scanning electron microscope, transmission electron microscopy, X-ray diffraction and Brunauer-Emmett-Teller. The results reveal that the NiCo 2 S 4 nanotubes with a uniform diameter of about 200 nm tightly anchor onto the crumpled surface of graphene sheets and GO sheets self-assemble into an interconnected porous structure. When the composites are evaluated as an anode for lithium-ion batteries (LIBs), presenting an extremely admirable cycling stability (967.5 mAh g −1 after 100 cycles at a current density of 100 mA g −1) and excellent rate capability (as high as 654.7 mAh g −1 at a large rate of at 2000 mA g −1). This work proved that the NGAs may have a great application in LIBs.