Oxygen-functionalized graphitic carbon nitride nanosheets/Co(OH)2 nanoplates anchored onto porous substrate as a novel high-performance binder-free electrode for supercapacitors

Abstract

Abstract In this work, binder-free composite of Co(OH)2 nanosheets/oxygen-functionalized g-C3N4 (f-g-C3N4) was co-embedded onto nickel foam through a simple one-step deposition process. In this process, f-g-C3N4 and Co(OH)2 are electrochemically co-embedded into Ni-Foam support using a simple electrodeposition procedure in a two-electrode system from an aqueous electrolyte containing both f-g-C3N4 and cobalt nitrate salt. FE-SEM and TEM observations confirmed that Co(OH)2 nanosheets are hierarchically formed on the surface of porous f-g-C3N4 electrophoretically deposited onto the surface of nickel foam making unique three-dimensional porous networks. The specific capacitances of Co(OH)2@f-g-C3N4/Ni-foam hybrid electrode were measured to be 1663 F g–1 and 1064 F g–1 at 1 A g–1 and 30 A g–1, respectively, which are higher than those of pristine Co(OH)2/Ni-foam electrode (i.e. 1267 F g–1 and 462 F g–1 at 1 A g–1 and 30 A g–1, respectively). Furthermore, nanocomposite electrode exhibited high capacitance retentions i.e. 64.1% retention with increasing the applied load from 1 A g–1 to 30 A g–1, also 93.4% and 88.6% capacity stabilities after 5000 cycling at 2 A g–1 and 6 A g–1, where pristine Co(OH)2/Ni foam showed only 36.5% retention at high-rate discharging, and capacity stabilities of 84.6% and 69.1% at 2 A g–1 and 6 A g–1, respectively. These improvements were ascribed to the synergetic effects between Co(OH)2 nanosheets and oxygen-functionalized g-C3N4, which supported the fabricated nanocomposite as a new high-performance electrode material for supercapacitors.