Synthesis of oxygen-functionalized biomass-based activated carbon as supercapacitor with improved electrochemical performance.

This study investigates the influence of oxygen functional groups in biomass-based activated carbon (AC) as an efficient, high-performance supercapacitor electrode. To create activated carbons with variable oxygen concentration, the surface of produced AC was altered using oxygen as an oxidizing agent at various temperatures. Nitrogen adsorption–desorption isotherms, scanning electron microscopy (SEM), energy dispersive X-ray analyzer (EDX) analysis, thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR) spectroscopy, Boehm titration and X-ray Photoelectron Spectrometer (XPS), are used to characterize the physico-chemical characteristics of the obtained carbons. Afterward, cyclic voltammetry, constant current charge–discharge and electrochemical impedance spectroscopy (EIS) were used to evaluate the electrochemical properties and behavior of ACs based electrodes. Indeed, the oxidative treatment increases the oxygen functional content while reducing the specific surface area. According to the results of the characterization, the electrode test reveals that the modified materials improve the electrochemical properties and enhance the material's double-layer capacitance. The AC treated with oxygen at 623 K displayed outstanding capacitance of 550 F g−1 at specific current of 0.1 A g−1 in NaOH (2 M) electrolyte and exhibits an excellent stability after 1000 cycles with a capacitance retention of 85.5%. In addition to being inexpensive, the prepared materials have excellent electrochemical performance and good stability, which make them appropriate for supercapacitor applications. [ABSTRACT FROM AUTHOR]