One-step synthesized N-doped graphene-based electrode materials for supercapacitor applications

Abstract

In this work, a novel one-step environmentally benign procedure for preparing nitrogen-doped graphene electrodes for high performance supercapacitors has been demonstrated for the first time, called Yucel's method. N-doped graphene-based electrodes were synthesized in a short time, at room temperature, one step (no need for a second process for doping) and low-cost by the using of Yucel's method without harmful oxidizing and reducing chemicals. During the production of N-doped graphene-based electrodes by this method, which functional group will form on the graphene surface is determined by controlling the applied potential range. Also, a detail mechanism has been proposed for the incorporation of these functional groups on the graphene structure produced by Yucel's method for the first time in literature. Since the chemical and morphological structure of each electrode is different, specific capacitance values are also different. The electrodes synthesized in a narrower synthesis potential range have shown higher capacity thanks to the catalytic effects of oxygenated functional groups (NO2, =COOH, =OH etc.) on their surfaces. Indeed, the relations between N including functional groups and specific capacitance properties of the electrodes were investigated in detail. After electrochemical, spectroscopic, and microscopic characterization of the materials, cyclic charge-discharge tests were carried out for 1000 cycles. The specific capacitance of the electrodes changed from 178 mF.cm(-2) to 2034 mF.cm(-2) in 10 mA.cm(-2) current density as a function of the mesoporous structure. This structure type becomes more accessible for electrolyte penetration as the number of cycles increases.