High-performance supercapacitor electrode of Cu2ZnSnS4 (CZTS) thin films grown by ECD†

Abstract

In this paper, we studied the capacitive performance of a kesterite Cu₂ZnSnS₄ (CZTS) electrode grown on an ITO (indium tin oxide) substrate by an electrochemical deposition technique (ECD) at room temperature for the first time. It was then annealed at 580 °C for an hour in a N₂ atmosphere with sulfur powder. The X-ray diffraction (XRD) analysis of the CZTS sample revealed it to have a tetragonal crystal structure, with characteristic peaks (2 2 0) and (1 1 2) corresponding to the kesterite phase. The Raman spectrum of CZTS thin films (TFs) displayed a prominent peak at around 324 cm⁻¹. The surface morphology typically demonstrated that the growth was spread across the entire surface, with each region displaying similar, yet heterogeneous structures at varying depths. From cyclic voltammetry (CV), at a scan rate of 1 mV s⁻¹, the specific capacitance value was determined as 1483 F g⁻¹, while it was calculated as 73 F g⁻¹ for a scan rate of 100 mV s⁻¹. Also, from galvanostatic charge–discharge measurement, the specific capacitance value of an electrode comprising CZTS TFs was determined to be 1695 F g⁻¹ at a current density of 1 A g⁻¹, while this value was 277 F g⁻¹ at a current density of 10 A g⁻¹. It has been discovered that electrochemically produced CZTS TFs exhibit excellent supercapacitive performance.