Facile one-pot synthesis of a NiMoO4/reduced graphene oxide composite as a pseudocapacitor with superior performance

Abstract

A hybrid NiMoO₄/rGO composite was successfully synthesized by a facile one-pot hydrothermal method. A series of characterization techniques: SEM, TEM, XRD, Raman, XPS and N₂ adsorption/desorption isotherms were used to verify the special nanostructure and unique composition of the as-prepared products, in which the NiMoO₄ nanowires are homogenously distributed in the interconnected rGO network, and at the same time the NiMoO₄ nanowires are encapsulated within the rGO sheets, further preventing the rGO nanosheets from agglomerating and restacking. As an electrode material for pseudocapacitors, the NiMoO₄/rGO composite exhibited a maximum specific capacitance of 1202 F g⁻¹ at 1 A g⁻¹, and still remained as high as 775 F g⁻¹ at 10 A g⁻¹ and 592 F g⁻¹ at 20 A g⁻¹, which are superior to those of pure NiMoO₄ nanowires. The enhanced capacitive performance of the as-prepared NiMoO₄/rGO composite is closely related to the form of an internal mesoporous structure by utilizing the high electrical conductivity and large surface area of rGO nanosheets, which could provide more electroactive sites, a larger electrode–electrolyte contact area and accelerate effective ion and electron transport in the whole electrode. The results suggest that such a hybrid electrode has great potential applications in high performance energy-storage systems.