Hybrid Co(OH)2/nano-graphene/Ni nano-composites on silicon microchannel plates for miniature supercapacitors

• Nano-nickel is deposited by flowing deposition method as the current collect.
• Active materials Co(OH)2 are deposited on nanographene (NG) on MECN.
• Co(OH)2/NG can be scanned faster than Co(OH)2 in CV because of high conductivity.
• The Co(OH)2/NG composite exhibits a stable capacitance of 3.522 F/cm2 (880.5 F/g).
• The retention ratio of Co(OH)2/NG composite is 99% after 5000 cycles.

Nano-scale Co(OH)2/NG (nano-graphene: NG) composites serving as the active materials of miniature supercapacitors are deposited on macroporous electrically conductive network (MECN). The Co(OH)2/NG composite in the channels largely contribute to the capacitance. The electrochemical properties are investigated by cyclic voltammetry (CV), galvanostatic charging-discharging, and electrochemical impedance spectroscopy (EIS) in a 2 M KOH solution. The Co(OH)2/NG composite exhibits a stable capacitance of 3.522 F/cm2 (880.5 F/g) and retention ratio is 99% after 5000 cycles demonstrating the stability and durability. The Co(OH)2/NG/MECN can be scanned faster than Co(OH)2/MECN in CV because of the higher conductivity.