Highly dispersed Co-Mo sulfide nanoparticles on reduced graphene oxide for lithium and sodium ion storage

A novel hybrid, highly dispersed spinel Co-Mo sulfide nanoparticles on reduced graphene oxide (Co₃S₄/CoMo₂S₄@rGO), is reported as anode for lithium and sodium ion storage. The hybrid is synthesized by one-step hydrothermal method but exhibits excellent lithium and sodium storage performances. The as-synthesized Co₃S₄/CoMo₂S₄@rGO presents reversible capacity of 595.4 mA·h·g^-1 and 408.8 mA·h·g^-1 after 100 cycles at a current density of 0.2 A·g^-1 for lithium and sodium ion storages, respectively. Such superior performances are attributed to the unique composition and structure of Co₃S₄/CoMo₂S₄@rGO. The rGO provides a good electronically conductive network and ensures the formation of spinel Co₃S₄/CoMo₂S₄ nanoparticles, the Co₃S₄/CoMo₂S₄ nanoparticles provide large reaction surface for lithium and sodium intercalation/deintercalation, and the spinel structure allows fast lithium and sodium ion diffusion in three dimensions.