Nitrogen-doped carbon quantum dots (N-CQDs)/Co3O4 nanocomposite for high performance supercapacitor

Abstract

The search of low cost, highly competent electrode material is the hot research area for various next-gen applications. Herein, cost effective nitrogen doped carbon quantum dots (N-CQDs) anchored in cobalt oxide (Co3O4) nanocomposite was fabricated through a simple hydrothermal method. The fabricated N-CQDs/Co3O4 nanocomposite showed high specific surface area (BET) of ~880 m2 g−1 with BJH pore size and volume of ~21 nm, 0.81945 cm3 g−1 respectively. The electrochemical performance through cyclic voltammetry (CV) in 3-electrode systems exhibited an improved specific capacitance of 1782 F g−1 at 5 mV s−1 in 6 M KOH electrolyte. Additionally, galvanostatic charge–discharge (GCD) analysis showed an improved capacitive performance with a specific capacitance of 1867 F g−1 at 1 A g−1 current density. The energy density was calculated 36.9 Wh kg−1 at the power density of 480 W kg−1. The capacitance retention graph demonstrates 96% stability through 500 GCD cycles.