Novel high energy density electrodes based on functionalized/exfoliated molybdenum oxide nanoflakes for high-performance supercapacitors

Abstract

Energy storage via electrochemical supercapacitors (ECSC) is critical for regulating and implementing intermittent renewable resources and enhancing the development of electric vehicles. In this paper, novel adenine/sulfanilamide functionalized molybdenum oxide (FMO) nanoflakes are synthesized by anodizing exfoliation followed by a simple hydrothermal method. The structural and optical properties of the FMO nanoflakes are elucidated by X-ray diffraction (XRD), Fourier transforms infrared (FT-IR), field emission scanning electron microscopy (FESEM), Raman spectroscopy, thermogravimetric analysis (TGA), UV–vis spectroscopy, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The electrochemical behavior of the synthesized materials has been evaluated in 1 M Li2SO4 using cyclic voltammetry (CV), galvanostatic charge/discharge, and electrochemical impedance spectroscopy (EIS). The FMO electrodes display a high specific capacitance of 1261.9 F/g at 1 A/g with an outstanding cycle life of 99.8 after 1000 cycles and 94.9% after 3000 cycles at 10 A/g. The fabricated FMO-based symmetric supercapacitor device delivers superior energy and power densities of 87.1 Wh/kg and 2116W/kg, respectively, at 2 A/g. The superior supercapacitive performance of FMO is correlated to the improved wettability, unstacking of the MoOx nanoflakes, and enrichment with oxygen vacancies. These results indicate the significant potential of FMO as an electrode material for highly capacitive ECSC.