Chemical synthesis of nano-grained ytterbium sulfide thin films for supercapacitor application

Abstract

Nano-grained ytterbium sulfide (Yb2S3) thin film is deposited by an inexpensive chemical bath deposition (CBD) method with excellent supercapacitive performance. The formation of Yb2S3 thin film is confirmed from XRD, FT-Raman, and XPS studies. The nano-grains like surface morphology of Yb2S3 thin film is observed using scanning electron microscopy and transmission electron microscopy techniques. The Yb2S3 film shows hydrophilic nature with a contact angle value of 61.2°. The electrochemical supercapacitive properties of Yb2S3 thin film are studied using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques. The Yb2S3 thin film exhibits a specific capacitance of 184.6 F g−1 in 1 M KOH electrolyte at a 5 mV s−1 scan rate. The symmetric solid-state supercapacitor device of configuration Yb2S3/KOH-PVA/Yb2S3 shows a specific capacitance of 15 F g−1 and energy density of 13.80 W kg−1 at power density 0.55 kW kg−1. The device exhibits 78% capacitive retention over 3000 cycles.