A new squaraine-triazine based covalent organic polymer as an electrode material with long life and high performance for supercapacitors

Abstract

A new two-dimensional covalent organic polymer material (ST-1) was synthesized by the condensation of squaric acid and melamine. The preparation is simple and cheap. Fourier transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy (XPS), N₂ adsorption–desorption, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) were employed to characterize the structure and properties of ST-1. This material presents the highest specific capacitance value of 177.6 F g⁻¹ at a current density of 0.3 A g⁻¹ in a three electrode configuration in a 6 M potassium hydroxide electrolyte. The retention rate of the specific capacitance can be maintained at about 60.24% when the current density is increased by 50 times. It is worth mentioning that ST-1 also demonstrates about 94% capacitance retention after 10 000 galvanostatic charge–discharge cycles.