Effect of solvent for tailoring the nanomorphology of multinary CuCo2S4 for overall water splitting and energy storage

Tailoring the nanomorphology of electrochemically active materials could significantly affect their resultant catalytic and charge storage performance. In this study, the nanostructured morphology of multinary CuCo2S4 and CuCo2S4 was tuned using a different volume concentration of water and ethanol resulting in different nano-shapes maintaining similar crystal structure. The electrocatalytic performance was analyzed for all the synthesized samples as the hydrogen (HER) and oxygen evolution catalyst (OER). The HER and OER study for CuCo2S4 sample synthesized using ethanol required a low overpotential of 158 mV to reach 10 mA/cm(2) and 290 mV to achieve 20 mA/cm(2) , respectively. Furthermore, the electrolyzer cell using symmetrical electrodes required a low overall cell potential of 1.66 V to achieve a current density of 10 mA/cm(2) and maintained stable performance for over 24 h, suggesting a promising bifunctional catalytic behavior. Furthermore, the synthesized samples were studied as electrodes for high-performance energy storage systems. The CuCo2S4 electrode showed an areal capacitance of 6.3 F/cm(2) (3190.8 F/g) at a current density of 2 mA/cm(2) . The Ragone plot for the areal energy versus power density resulted to be 265 mWh/cm(2) (132 Wh/kg) and 11.9 W/cm(2) (5973 W/kg), respectively. Thus, from the overall study, it can be confirmed that tailoring morphology of nanostructured material such as CuCo2S4 could be a promising way for the advancement of energy generation and storage devices. (C) 2019 Elsevier B.V. All rights reserved.