Deciphering the hype effect of Ni-foam substrate in electrochemical supercapacitors: Is there a way out?

Abstract

Despite the subtle effects of the current collector on the overall supercapacitor performance, the substrate parasitic reactions have rarely been reported. Specifically, for the widely used Ni foam (Ni-F) current collector, the redox reaction of the Ni-F oxide layer is usually being confused with the true electrochemical signature of the active electrode materials. Herein, we studied electrodeposited MnS, CoS, and NiS active materials on two different substrates (Ni-F and carbon cloth (CC)). The study revealed that the sulphides deposited on Ni-F showed overestimated higher capacitance values than those deposited on CC. However, the retention and the rate capability were higher for those films deposited on CC. Furthermore, Ni-F was found to interfere with the redox reactions of MnS and CoS but not NiS. Moreover, Ni-F altered the charge storage mechanism of the electrodes. The results confirmed the interference of Ni-F with the deposited materials giving misleading primary results. On contrary, CC is an alternative high performance, flexible, and stable substrate.