Preparation and characterization of CoWO4/CoMn2O4 nanoflakes composites on Ni foam for electrochemical supercapacitor applications

Abstract

• Well-defined CoWO4/CoMn2O4 nanoflakes composites, CoWO4 worm like structures and CoMn2O4 dandelion-like structures were in situ grown on Ni foam via a simple one-step hydrothermal method. • The synergetic effect between integrated materials CoWO4 and CoMn2O4 played significant impact on electrochemical properties of the supercapacitors. • Compared to CoWO4 and CoMn2O4 electrode, the CoWO4/CoMn2O4 electrode delivered a high specific capacitance of 2259.6 F g-1 at 2 A g-1, and superior cycling stability with retention of ~92.6 % after 3000 cycles at 6 A g-1. A simple synthesis method for hybrid transition metal oxides is important for their application in electrode materials. In this present work, we reported one-pot hydrothermal method to synthesize CoWO 4 /CoMn 2 O 4 nanoflake composites. The prepared CoWO 4 /CoMn 2 O 4 nanoflakes composite electrodes were comprehensively characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Electrochemical capacitive behaviour of the electrodes fabricated on a nickel foam substrate were evaluated by cyclic voltammetry (CV), galvanostatic charge/discharge cycling (GCD) and electrochemical impedance spectroscopy (EIS) techniques in 3 M KOH aqueous electrolyte solution. The results show that the CoWO 4 /CoMn 2 O 4 nanoflake composites possess an excellent specific capacitance of 2259.6 F g −1 at the current density of 2 A g −1 . In addition, the CoWO 4 /CoMn 2 O 4 nanoflakes show excellent cycling stability (92.6 % capacity retention after 3000 cycles) than CoWO 4 (78.3%) and CoMn 2 O 4 (85.7%). These attractive results suggest that these CoWO 4 /CoMn 2 O 4 nanoflake composites have great potential as an electrode material for the next generation of high-performance electrochemical supercapacitors.