Carbon nanomaterials supported Ni(OH)_2/NiO hybrid flower structure for supercapacitor

摘要

In this study, flower-shaped NiO/α-Ni(OH)_2 hybrid structures were synthesized by a solvothermal process. The microstructure, surface morphology, and surface area of the synthesized materials were characterized by XRD, SEM, and BET. It was discovered that this unique hybrid structure exhibits outstanding capacitive performance in basic electrolyte. From galvanostatic charge-discharge test, the hybrid composite itself demonstrates a solid capacitance value of 707 F/g at 2 A/g and 474 F/g at a high discharge rate of 10 A/g. In order to further improve the performance and the capacitance retention with enhanced current density, carbon nanomaterials were used as supports for the NiO/α-Ni(OH)_2 hybrid. These carbon nanomaterials are believed to form conductive network around NiO/α-Ni(OH)_2 flowers. The effects of 4 different carbon nanomaterial supports, including carbon black, carbon nanotubes, and graphene, were thoroughly investigated, and specifically the addition of single-walled carbon nanotubes to the composite significantly enhanced the performance to 810 F/g at a high current discharge of 10 A/g. Moreover, this carbon supported hybrid composite exhibits an impressive specific power density of 7200 W/kg and a steady energy density of 21 W h/kg.