Flower-like Cu1.8S nanostructures for high-performance flexible solid-state supercapacitors

Abstract

In wearable and portable electronic devices, small size, light weight, flexibility, and easy operability are necessary for energy storage systems, such as battery and supercapacitor. To improve the performance, high specific capacity and high energy and power densities are also required. In this study, flower-like Cu1.8S nanostructures are synthesized from a single source tris(thiourea)copper(I) chloride complex precursor. The different-sized Cu1.8S nanostructures with flower-like petal morphology are successfully synthesized by addition of capping agents such as sodium dodecyl sulfate (SDS) and ethylenediaminetetraacetic acid (EDTA) with ethylene glycol (EG) as a solvent. The petal thicknesses vary from 60 to 30 nm, resulting in the increase in its specific surface area. The as-prepared nanostructures are tested for their supercapacitor performances in KOH electrolyte medium. The EDTA-Cu1.8S electrode provides a high specific capacitance of 1050.0 F g−1 as compared with SDS-Cu1.8S (773.0 F g−1) and EG-Cu1.8S (625.4 F g−1). Flexible solid-state symmetric supercapacitors are also fabricated from EDTA-Cu1.8S which deliver a high volumetric capacitance (4.5 F cm−3) and energy density (0.5 mWh cm−3).