Performance of solid-state symmetric supercapacitors based on Dy2S3 electrodes

Rare earth metal sulfides show good capacitance retention and better charge discharge performance. Dysprosium based materials could be a promising candidate for the utilization in supercapacitors due to it's multiple transition states. The dysprosium sulfide (Dy2S3) thin films were deposited on stainless steel (SS) substrate using facile successive ionic layer adsorption and reaction (SILAR) method. The films exhibits orthorhombic crystal structure and spherical nanoparticles morphology. The electrochemical supercapacitive performance of Dy2S3 film showed maximum specific capacitance (Cs) of 273 F g−1 at a scan rate of 5 mV s−1 with excellent (83 %) cycling performance over 2000 cycles in 1 M Na2SO4 electrolyte. The industrial application of SILAR deposited Dy2S3 thin film was examined by fabricating flexible solid-state symmetric supercapacitor (FSS-SSC) device with configuration Dy2S3/PVA-Na2SO4/Dy2S3. It exhibited Cs of 26 F g−1 with specific energy of 17 Wh kg−1 and specific power of 520 W kg−1. A good cyclic stability was observed with capacitive retention of 79 % at the scan rate of 100 mV s−1 after 5000 cyclic voltammetry (CV) cycles. This study highlights the potential application of Dy2S3 for supercapacitor application.