One-pot synthesis of CoxSy nanomaterials for high-performance supercapacitors

In the present work, we report a convenient method for preparing non-stoichiometric cobalt sulfide with one-pot solvothermal method. Different CoxSy nanomaterials are synthesized for supercapacitor application. This experiment explores the influence of ethanol and N,N-dimethylformamide (DMF) on the microstructure and properties of CoxSy. X-ray diffraction (XRD), scanning electron microscopy, and Brunner-Emmet-Teller (BET) measurements demonstrated that CoxSy(ethanol) and CoxSy(DMF) have different structures and morphologies. Electrochemical supercapacitor performance of CoxSy(ethanol) and CoxSy(DMF) is characterized via cyclic voltammetry, galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) measurements. These results show that CoxSy(DMF) has better electrochemical performance than CoxSy(ethanol), and its capacitance can reach 347.4 F/g at the current density of 0.5 A/g. Moreover, CoxSy(DMF) also delivers a better cycling stability of about 70.8% capacity retention after 3000 cycles at a current density of 4 A/g. In addition, the assembled asymmetric supercapacitor of CoxSy(DMF)//active carbon shows an excellent energy density of 66.4 Wh/kg at a power density of 483.1 W/kg. These results indicate that CoxSy(DMF) has a good application prospect in the field of supercapacitor.

Automated summary

This study reports a convenient method for preparing non-stoichiometric cobalt sulfide via one-pot solvothermal method, and explores the influence of DMF and ethanol on the microstructure and properties of CoxSy. The results show that CoxSy(DMF) exhibits better electrochemical performance and cycling stability compared to CoxSy(ethanol), indicating good application prospects in the field of supercapacitors.