Investigation of Cu2SnS3 nanoparticles decorated g-C3N4 nanocomposites for high performance battery-type hybrid supercapacitors

The hybrid-type of supercapacitors based on transition metal sulfides-carbon composite electrodes are found to be a prominent and emerging technological advancement with beneficial characteristics such as a larger surface area, high durability, and a unique charge storage mechanism. In this work, phase pure copper tin sulfide (Cu₂SnS₃/CTS) nanoparticles (NPs) and the nanocomposite of CTS NPs decorated graphitic carbon nitride (g-C₃N₄) CTS-gCN were prepared by an inexpensive solvothermal approach. The CTS-gCN nanocomposite-based supercapacitors show a high specific capacitance of 477 F/g at 1 A g⁻¹ current density, which is much higher than the pristine CTS NPs based supercapacitors (362 F/g) in three electrode configurations. The asymmetric hybrid supercapacitors were prepared with CTS-gCN electrodes and reduced graphene oxide (rGO) as a negative electrode with potassium hydroxide (KOH) as an electrolyte. The electrochemical characteristics of asymmetric CTS-gCN//rGO supercapacitors exhibit battery-like behavior with a specific capacitance of 108 F/g at the scan rate of 1 A g⁻¹ with a high energy density of 42 W h kg⁻¹ and a power density of 835.4 W kg⁻¹. The CTS-gCN//rGO supercapacitors show excellent capacitance retention over 94 % even after 2000 cycles. The obtained electrochemical results of the supercapacitors with high energy density, power density, wider potential window, and cyclic stability suggest the CTS-gCN//rGO hybrid supercapacitors as a promising candidate for emerging electrochemical energy storage technologies.