3-D honeycomb NiCo ₂ S ₄ with high electrochemical performance used for supercapacitor electrodes

A new nanostructured 3-D honeycomb NiCo ₂ S ₄ (NC-1) has been successfully prepared by a simple hydrothermal method assisted sulfuration procedure. The morphology of the 3-D honeycomb was investigated by FESEM and TEM, and the results suggest the NC-1 has a highly porous structure. Its chemical composition was characterized by XRD and XPS and the results indicate that the NC-1 is the pure phase of NiCo ₂ S ₄ . In order to study the effect of morphology on the electrochemical performance, we have also prepared needle-, flake- and petal-like nanostructured NiCo ₂ S ₄ on Ni foam. When they were used as supercapacitor electrodes, the NC-1 exhibited the highest electrochemical performance among these four kinds of electrodes. Its maximum specific capacity was over 14 mAh cm ⁻² at 1 mA m ⁻² and it still yielded 7.96 mAh cm ⁻² even at 50 mA cm ⁻² . The NC-1 remained 99.64% of the initial capacity after the long-term test of 1000 cycles. Consequently, the NC-1 has the promising potential as an energy storage system in the future and it can also be used as an ideal substrate for other active materials involving a faradaic process.