Carbon quantum dots (CQDs)/Ce doped NiO nanocomposite for high performance supercapacitor

A cost effective novel carbon quantum dots/Ce-doped nickel oxide (CQDs/Ce-NiO) nanocomposite was synthesized via hydrothermal route. An exceptional BET surface area of 731 m(2) g(-1) and mesoporosity (similar to 17 nm) was estimated. In three-electrode system an excellent electrochemical behaviour was demonstrated by CQDs/Ce-NiO nanocomposite with high specific capacitance of similar to 2487 F g(-1) by cyclic voltammograms at a scan rate of 5 mV s(-1) and similar to 2513 F g(-1) by galvanostatic charge-discharge at a current density of 0.5 A g(-1) in 6M KOH electrolyte. This may be owing to elegant redox activity of Ce3+/Ce4+ ions and high conductivity of CQDs. The capacitance retention was found similar to 97 % after 2000 GCD cycles.