Oxygen-functionalized g-C3N4 layers anchored with Ni(OH)2 nanoparticles assembled onto Ni foam as binder-free outstanding electrode for supercapacitors

In this paper, a facile co-electrophoretic/electrodeposition method is reported to simple embedding a binder-free composite of porous oxygen-functionalized graphitic carbon nitride (O@g-C3N4)/nickel hydroxide nanoparticles (Ni(OH)2 NPs) into porous nickel-foam (NF) support. The prepared samples are analyzed using FT-IR, Raman, XRD, TGA/DSC, FE-SEM and TEM techniques. The analyses results proved formation of mixed α/β-Ni(OH)2 NPs onto the surface of O@g-C3N4 layers electrophoretically embedded onto NF support. The electrochemical charge storing ability of the fabricated O@g-C3N4/Ni(OH)2/NF electrode was evaluated in KOH electrolyte, and its specific capacity value was calculated to be as high as 967 C g−1, which was higher than those of pristine Ni(OH)2/NF and O@g-C3N4/NF electrodes (i.e. 754.8 C g‒1 and 287 C g‒1, respectively). Furthermore, O@g-C3N4/Ni(OH)2/NF exhibited an outstanding cycling stability of 94.4% after 5000 cycles at 3 A g‒1, which was higher than the long-term stability delivered by Ni(OH)2/NF electrode (i.e. 77.5% at 3 A g‒1). EIS data revealed that the fabricated O@g-C3N4/Ni(OH)2/NF hybrid electrode had lower internal resistance and smaller charge transfer resistance confirming its higher charge transfer rate and better electrical conductivity in comparison to pristine Ni(OH)2/NF electrode. •Oxygen-functionalized g-C3N4 was prepared though a simple chemical oxidation method.•O@g-C3N4/Ni(OH)2 electrode was fabricated through a one-pot deposition method.•The fabricated hybrid electrode displayed superior synergetic performance.•Superior capacity retention of 94.4% was observed after 5000 cycles at 3 A g–1.