In situ grown cockscomb flower-like nanostructure of NiCo_2S_4 as high performance supercapacitors

摘要

Cockscomb flower-like NiCo_2S_4 composite material is made for supercapacitor application by using two step hydrothermal processes. The cockscomb flower-like NiCO_2S_4 architecture contains numerous ultrathin folded nanosheets which increases the active areas of the electrode and the three dimensional open space between the flower sheets facilitates the easy flow of electrolyte ions and leads to efficient utilization of active materials even at high current densities. Two kinds of composite electrodes were fabricated by coating and in situ growing a cockscomb flower-like of NiCo_2S_4 on nickel foam current collector. The in situ grown cockscomb flower-like NiCo_2S_4 showed superior performance compared to cockscomb flower-like of NiCo_2S_4 coated on nickel foam by avoiding the uses of polymer binders which adds dead areas and increase resistance on the electron and ion diffusion. Using this advantage the in situ grown cockscomb flower-like of NiCo_2S_4 showed high specific capacitance of 1707 F/g at current density of 1 A/g and areal capacitance of 4.1 F/cm_2 at current density of 2.4 mA/cm_2 with good rate capability of 65.12 % as current increases from 2.4 to 80 mA/cm_2. Such excellent conductive and stable structure may find potential application in future energy storage devices.