Phosphoric acid functionalized carbon dots for supercapacitor applications

Abstract

The improvement of energy storage technologies with green materials is essential for a sustainable future. In this study, oleic acid carbon dots (CDs) were functionalized with phosphoric acid to find its influence on Ni-foam electrodes for supercapacitor applications. The carbon dots and electrodes were characterized using UV–Vis, PL, FT-IR, FESEM, TGA, and DSC. The changes in morphology, thermal stability, and other characteristics of Ni-foam with the incorporation of carbon dots have been discussed. Specifically, phosphoric acid functionalized CDs have been found to possess a unique granular distribution on the electrode with lower thermal stability than bare Ni-foam. Electrochemical investigation involved CV, GCD, and EIS techniques. The results from electrochemical tests indicate an enhancement in the electrochemical performance of Ni-foam with the addition of functionalized CDs. CV results indicate quasi-reversible peaks for the studied systems. A lowering in resistance with the addition of phosphoric acid functionalized CDs was concluded and the specific capacitance was obtained to be 2.08 Fg Overall, this study will also help in understanding the changes in physical and electrochemical characteristics of electrodes with the addition of functionalized CDs.