A Nitrogen-Rich Triazine-Based Covalent Organic Polymer Decorated with Nickel for Supercapacitors

A nitrogen-rich triazine-based covalent organic polymer (COP) was made from melamine and cyanuric chloride through a solid-state grinding process. The poor electrochemical performance due to low nitrogen content and structural instability has been overcome in this process. To enhance active sites, nickel was doped into the COP. Fourier transform infrared (FTIR) analysis confirmed successful polymerization, the release of chlorine, and the presence of nickel oxide. X-ray diffraction (XRD) patterns indicated that the crystalline form of the COP remained intact after nickel incorporation. Scanning electron microscopy (SEM) images displayed a change from smooth to a rough, granular texture due to nickel's interaction within the polymer matrix. Electrochemical tests demonstrated the better performance of the nickel-doped COP, showing a specific capacitance of 40 Fg^-1 at 5 mVs^-1 (cyclic voltammetry, CV) and 23 Fg^-1 at 0.1 Ag^-1 (galvanostatic charge/discharge, GCD), with a maximum power density of 835 Wkg^-1 at 5 mVs^-1. Notably, the electrode showed great cycling stability, maintaining almost 70% of its initial capacitance after repeated charge and discharge cycles. The results show that triazine-based COPs doped with nickel have potential for application in the use of supercapacitors due to their stability, efficiency, and duration.