Laser-nanostructured Ni-Fe electrodes for improved supercapacitor-electrolysers systems

There is an increasing interest in developing an Ni-Fe supercapacitor-electrolyser system (SCES) for electricity storage and efficient hydrogen production. In this study, periodic nanostructures on nickel [(& lambda;Ni = 570 & PLUSMN; 30) nm] and on iron sheets [(& lambda;Fe = 553 & PLUSMN; 6) nm] have been fabricated and were used as electrodes in an alkaline SCES. Their efficiency was compared to untreated nickel and iron sheets. The electrochemical evaluation of the nanostructured electrodes showed lower overpotential (& eta;10 and & eta;100) and lower Tafel slope for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The hydrogen production efficiency of the lasernanostructured electrodes was significantly enhanced. Moreover, the laser-nanostructured electrodes' doublelayer capacitance (CDL) values were increased 1.5 times for laser-nanostructured Fe electrodes and 5.3 times for laser-nanostructured Ni electrodes. These results show the potential of the fabricated electrodes in applications serving a dual purpose, i.e., enhanced hydrogen production and increased charge storage.

Automated summary

In this study, periodic nanostructures on nickel and iron sheets were fabricated and used as electrodes in an alkaline SCES. The electrochemical evaluation showed improved hydrogen production efficiency and increased charge storage capacity of the nanostructured electrodes.