A novel high-performance supercapacitor based on the innovated ternary CeO2@CoWO4/N-doped graphene nanocomposites

• Novel ternary CeO 2 @CoWO 4 /N-doped graphene nanocompositeare is synthesized in facile method. • The synthesized nanocomposites show specific capacitance of 698.18 F g −1 at 3 A g −1 . • It is exhibited superior cycling stability 91.8 % capacity retention after 1000 cycles. The present work used multiple steps method to fabrication the three component CeO 2 @CoWO 4 /N-doped graphene (CCNG) as active material for supercapacitor application for the first time. For this purpose, firstly CoWO 4 nanostructure was synthesized via hydrothermal route, after that CeO 2 nanoparticles were sonochemicaly grown on CoWO 4 nanostructures followed by thermal treatment and overall, CCNG nanocomposites were synthesized through the hydrothermal approach in presence of urea as nitrogen source. As-designed materials were physico-chemically characterized by field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy and Brunauer-Emmett-Teller (BET) tests. The electrochemical capacitive of as-fabricated nanostructures were investigated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) technologies in 3.0 M KOH solution as electrolyte. Also, molar ratio of Ce 2+ : Co 2+ was optimized and CeO 2 @CoWO 4 with molar ratio 1:2 was selected as the best electrode with specific capacitance of 489.27 F g -1 at constant current density of 3 A g -1 . Likewise, the mass ratio of N-doped graphene to active materials was optimized and, CCNG-2 nanocomposites illustrated the highest specific capacitance of 698.18 F g −1 at 3 A g −1 , which was greater than that of bare CoWO 4 (295.64 F g −1 ) and CeO 2 (293.45 F g -1 ) at this condition. Furthermore, CCNG-2 nanocomposites exhibited superior cycling stability 91.8 % capacity retention after 1000 cycles at sweeping scan rate of 50 mV s -1 , while CeO 2 @CoWO 4 possessed 73.2 % capacity retention at 1000th cycles. These interesting results revealed that the CCNG-2 nanocomposites are capable as a active material for usage in high-performance electrochemical supercapacitors.