Surfactant-free one-pot hydrothermal growth of micro-flower-like copper tin sulfide electrode material for pseudocapacitor applications

Ternary Cu₂SnS₃ (CTS) metal chalcogenide is an important potential electrode material in the field of energy storage systems due to the tunnels in its crystal structure and good electrochemical properties. Herein, the CTS micro-flowers were successfully synthesized by a facile strategy of one-step hydrothermal method without the addition of any other surfactants or templates. The phase form, functional groups, and existence of the valence states in the prepared CTS powder sample were characterized by X-ray diffraction pattern, Fourier transform infrared spectroscopy, and the X-ray photoelectric spectroscopy, respectively. The CTS sample revealed flower-like morphology which was confirmed by field-emission scanning electron microscopy. In alkaline 1 M KOH electrolyte media, the cyclic voltammetry and galvanostatic charge-discharge curves of the micro-flower CTS electrode material were measured using a traditional three-electrode system. The electrochemical data exhibited a specific capacitance value of 183 F/g at 1 A/g of current density, and it maintained 56.2% specific capacitance retention (103 F/g) at higher current density (9 A/g), which is a good sign for rate capability of the electrode. Additionally, the micro-flower CTS electrode composite revealed 88.5% capacitance retention after performing 2000 cycles at 1 A/g of current density, indicating its good cycling stability.