SILAR synthesized nanostructured ytterbium sulfide thin film electrodes for symmetric supercapacitors

A simple and inexpensive successive ionic layer adsorption and reaction (SILAR) method was used for synthesis of ytterbium sulfide (Yb 2 S 3 ) thin film. The valence states and crystal structure of Yb 2 S 3 thin film material were identified using X-ray photoelectron spectroscopy and X-ray diffraction analysis, respectively. Wettability test of Yb 2 S 3 thin film showed hydrophilic nature with the value of 21.70°. The surface texture of Yb 2 S 3 thin film was examined using field emission scanning electron microscope (FE-SEM). The specific surface area and pore size distribution were measured using the Brunarer-Emmet-Teller (BET) and Barrette-Joynere-Halendar (BJH) methods. The supercapacitive performance of Yb 2 S 3 thin film was studied using cyclic voltammetry, galvanostatic charge discharge and electrochemical impedance tests in 1.0 M Na 2 SO 4 aqueous solution. The Yb 2 S 3 electrode showed specific capacitance ( Cs ) of 181 F g −1 with 83% capacity retention up to 3000 CV cycles. The aqueous symmetric supercapacitor (ASSc) device with the configuration of Yb 2 S 3 /Na 2 SO 4 /Yb 2 S 3 and solid-state symmetric supercapacitor (SSSSc) device of configuration of Yb 2 S 3 /PVA-Na 2 SO 4 /Yb 2 S 3 were fabricated. The ASSc device showed better supercapacitor performance (energy density (E.D.) of 8.25 Wh kg −1 at power density (P.D.) of 0.56 kW kg −1 ) than the SSSSc device.