Polyaniline/ZnS quantum dots nanocomposite as supercapacitor electrode

Abstract

Zinc Sulfide quantum dots (ZnS QDs) and polyaniline (PANI) were prepared by co-precipitation and chemical oxidation polymerization methods, respectively. PANI/ZnS QDs nanocomposites as a supercapacitor electrode are presented in this work for the first time. Electrochemical properties of PANI/ZnS QDs nanocomposites were measured in 1.0 M H2SO4 using cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance techniques (EIS). PANI/ZnS QDs exhibited maximum specific capacitance values of 893.75 and 929 F/g at 0.5 A/g and 5.0 mV/s, respectively. In addition, the energy density (E) and power density (P) of PANI/ZnS QDs electrode were 178.75 W h/kg and 300 W/kg, respectively with a good cyclic stability of 97.8% after 1000 GCD cycle. ZnS QDs reduced the series resistance of supercapacitor electrode due to their small size (less than 10.0 nm), high surface area, and this promotes the contact between PANI and electrolyte and improves the electrochemical performance. A graphite electrode and PANI/ZnS QDs electrode were assembled to fabricate an asymmetric supercapacitor (ASC) and produced a specific capacitance of 358 F/g at 0.5 A/g. ASC was found to has an E of 71.6 W h /kg and P of 290.3 W/ kg.