Fabrication and improvement in the electrochemical performance of a 2D g-C3N4-based symmetric supercapacitor device

Abstract

This work evaluates the possibility of employing 2-dimensional graphitic carbon nitride (2D g-C₃N₄) to be utilized in supercapacitor applications as an anode material. Compared to traditional carbon-based materials, g-C₃N₄ (CN) has various benefits, including higher energy-density and rate-capability. Therefore, we investigated the performance of a CN-based supercapacitor synthesized using an efficient and cost-effective thermal polymerization method. X-ray diffraction (XRD) data investigation indicated hexagonal symmetry composed with space group P-6 m2, indicating CN with no discernible presence of any other phases. The XRD pattern was utilised to calculate the average crystallite size, which was around 2.87 nm. In a three-electrode arrangement, electrochemical studies were performed on the CN electrode. The outcomes of this study revealed the specific capacitance (C_s) to be around 35.2 F/g at 5 mV/s when measured using cyclic voltammetry (CV) and was 39.9 F/g at 1.0 A/g when calculated by galvanostatic charge-discharge (GCD). Finally, the construction of 2D CN based symmetric supercapacitor device was manifested and its electrochemical performance was investigated. Electrochemical studies of the symmetric supercapacitor device demonstrated a highest cell specific capacitance (C_cell) of 149.1 F/g using GCD at 0.5 A/g. The symmetric supercapacitor device exhibited an extraordinary E_cell of 141.8 Wh/kg at a P_cell of 925 W/kg. Overall, this work thoroughly analyzed the electrochemical features of 2D CN and their symmetric supercapacitor devices, and offered insightful information on its prospective use in the energy storage field, which showed that 2D CN has better electrochemical performance than other similar materials.