Thermal stability on solid state symmetric supercapacitors with hydrothermally synthesized Cu₂CoSnS₄ electrodes

The effects of thiourea concentration on crystal phase, morphology, and the elemental composition and electrochemical characteristics (ECs) of hydrothermally synthesized Cu₂CoSnS₄ (CCTS) electrodes are systematically studied. In a three-terminal (3T) configuration, layered structure morphology with Cu-rich chemical composition-based electrodes exhibits higher ECs than other electrodes. The thermal reliability of devices up to 60℃ is practically validated via temperature-dependent cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) measurements for single symmetric solid-state supercapacitor (SSC) devices. The maximum of C_p=(251.87 ± 30.56)Fg⁻¹, E=(89.55 ± 10.35)Whkg⁻¹, P=(800 ± 40.32)Wkg⁻¹ and voltage window expanded up to 1.6 V including red LED operation for 6 min are achieved for the serially connected two SSCs at 1Ag⁻¹, indicating that CCTS can be one promising electrode material for SSCs.