High-performance symmetric supercapacitor; nanoflower-like NiCo2O4//NiCo2O4 thin films synthesized by simple and highly stable chemical method

Abstract

In this study, flowers-like interconnected nanoflakes NiCo2O4 thin films were synthesized by the SILAR method for the fabrication of supercapacitor application. X-ray diffraction analysis revealed that the synthesized NiCo2O4 thin films exhibit polycrystalline nature, and FE-SEM images confirmed their highly porous-like surface area. The analysis of structural, elemental, and compositional properties of the NiCo2O4 thin films were confirmed, that the thin films were used as electrode material for supercapacitor applications used as electrode material for supercapacitor testing. As expected, the prepared NiCo2O4 thin films showed high stability and served as efficient materials for use in supercapacitors application. The NiCo2O4 thin films exhibited excellent cycling charge-discharge with a specific capacitance (C-S) of 1936 F g(-1) at a scan rate of 5 mV s(-1) in a 3 M KOH electrolyte. Cycling stability results revealed that NiCo2O4 thin films exhibit highly stable performance with a 94.5% retention. Symmetric supercapacitor performance presenting an energy density of 294.54 kW h kg(-1) and power density 7.8 W kg(-1), it indicates the NiCo2O4 based electrode is applicable for the practical applications in device fabrication of asymmetric and symmetric supercapacitor. The high performance of the NiCo2O4 thin films is possibly related to the presence of a highly porous surface morphology and stepwise effects of the SILAR cycle. (C) 2019 Elsevier B.V. All rights reserved.