Supercapacitors Based on Spider Nest Shaped Nickel Foam Electrodes Operating in Seawater

Nickel foam was modified with multi-walled carbon nanotubes and β-cyclodextrins to fabricate the electrodes with conductive spider nest shaped multi-scale three-dimensional porous structure for assembling symmetrical supercapacitor. The chemical bond inside carbon nanotubes, π-π stack effects between carbon nanotubes, and physical adsorption between carbon nanotubes and nickel foam substrate were the main force to stabilize the spider nest structure. The role of β-cyclodextrins was dispersant to prevent agglomeration of carbon nanotubes, enhancing electroactive surface area of nickel foam, and improving specific capacitance of the electrodes. The electrodes had excellent rate capability. The obtained symmetrical supercapacitors exhibited good specific capacitance of 273.4 F g−1, energy density of 102.9 Wh kg-1, and excellent power density of 17561.3 W kg-1 with outstanding cycling stability for 4000 cycles. The supercapacitor had the ability to operate in seawater stably and had promising to be used as eco-friendly power supply to marine engineering equipment.