Facile synthesis of 3D porous Co₃V₂O₈ nanoroses and 2D NiCo₂V₂O₈ nanoplates for high performance supercapacitors and their electrocatalytic oxygen evolution reaction properties

Abstract

Binary metal oxides have recently attracted extensive attention from researchers in the energy storage and conversion field due to their high energy densities and multiple oxidation states. Novel 3D Co₃V₂O₈ porous rose-like structures and 2D NiCo₂V₂O₈ nanoplates were facilely synthesized via a solvothermal method, and the morphologies, Ni/Co ratios, and surface area of these samples can be easily tuned in the same procedure. The as-prepared Co₃V₂O₈ porous rose-like structure exhibited good electrocatalytic oxygen evolution performance with excellent activity and stability. In addition, 2D NiCo₂V₂O₈ nanoplates delivered a high specific capacitance of 1098.9 F g^-1 at 4 A g^-1 and good cycling stability (remaining 68% after 7000 cycles) in aqueous KOH electrolyte. The NiCo₂V₂O₈ nanoplates inherit the pseudocapacitive benefits of both Ni₃V₂O₈ and Co₃V₂O₈, showing a higher specific capacitance than pure Co₃V₂O₈ porous rose-like structures.