The fabrication of hierarchically porous carbon-coated nickel oxide nanomaterials with enhanced electrochemical properties

Abstract

In our current work, hierarchically porous carbon-coated nickel oxide nanoplates were successfully synthesized through Ni(OH)2 cladding with resorcinol and formaldehyde resin after subsequent carbonization process. The as-prepared NiO-coated carbon nanomaterials were examined, using TEM, XRD, Raman, XPS, TG and BET measurements. The optimized electrode (NiO/Ni@C-450 nanoplates) has regular hexagonal core–shell structure, uniform diameter and thickness. Owing to its porous core–shell structure, high specific surface area (457.03 m2 g−1) and high contents of Ni (6.43 at.%) and O (19.35 at.%) elements, NiO/Ni@C-450 electrode possesses the specific capacitance of 276.1 F/g at 0.5 A/g and good coulombic efficiency. Because the coated carbon layer enables to protect NiO structure and extends the cyclic life of electrode materials, the capacitance retention of NiO/Ni@C-450 electrode is 88.7% after 1000 cycles, which is much higher than that of NiO electrode. All these measured results demonstrate that the as-prepared NiO/Ni@C-450 nanoplate is supposed to be a promising material with easy preparation, high specific capacitance and good cyclic stability properties for potential applications in energy storage devices.