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 (Yb2S3) thin film. The valence states and crystal structure of Yb2S3 thin film material were identified using X-ray photoelectron spectroscopy and X-ray diffraction analysis, respectively. Wettability test of Yb2S3 thin film showed hydrophilic nature with the value of 21.70 degrees. The surface texture of Yb2S3 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 Yb2S3 thin film was studied using cyclic voltammetry, galvanostatic charge discharge and electrochemical impedance tests in 1.0 M Na2SO4 aqueous solution. The Yb2S3 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 Yb2S3/Na2SO4/Yb2S3 and solid-state symmetric supercapacitor (SSSSc) device of configuration of Yb2S3/PVA-Na2SO4/Yb2S3 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.