Synthesis of high-performance Mo2S3/NiS2-RGO anode materials and its applications in sodium-ion batteries and sodium-ion capacitors

Herein, molybdenum trisulfide/nickel disulfide-reduced graphene oxide (Mo 2 S 3 /NiS 2 -RGO) composites as anode material for sodium-ion batteries (SIBs) and sodium-ion capacitors (SICs) were synthesized by one-step facile hydrothermal method. Through electron microscopy analysis, it could be observed that the Mo 2 S 3 /NiS 2 nano-rods and nano-balls were dispersed uniformly over the two-dimensional RGO sheets. When tested as an anode material, Mo 2 S 3 /NiS 2 -RGO showed a considerable reversible capacity of 653.1 mA h g −1 at 100 mA g −1 after 50 cycles and capacity retention of 197.5 mA h g −1 at 5000 mA g −1 after 226 cycles. The sodium storage mechanism of Mo 2 S 3 /NiS 2 -RGO was explained by ex situ XPS. Furthermore, as-fabricated SICs delivered an excellent specific energy of 182.7 W h kg −1 (at 1120 W kg −1 ), and SIBs exhibited the discharge capacities of 85 mA h g −1 at 2 C. Overall, the superior electrochemical performances of Mo 2 S 3 /NiS 2 -RGO demonstrated that it was a promising anode materials to construct high-performance full cell.