Supercapacitor performances of polyethylene glycol-intercalated Co(OH)2 nanoflakes by potentiodynamic deposition

Each Co(OH)(2) and polyethylene glycol (PEG)-intercalated Co(OH)(2) was potentiodynamically deposited from nitrate bath and their supercapacitor performances examined. The deposited hydroxides were characterized by X-ray diffraction, scanning electron microscopy and Fourier transformed infra-red spectroscopy. The supercapacitor behaviour of the hydroxides was examined by cyclic voltammetry and galvanostatic charge-discharge studies in 1 M KOH electrolyte. It was observed that the specific capacitance of Co(OH)(2) could be tuned from 440 to 710 F g(-1) at a current of 0.5 A g(-1) by intercalating PEG into the interlayers of Co(OH)(2). In addition, the 5 vol.% PEG-intercalated Co(OH)(2) electrode exhibited highest specific capacitance and excellent cycle life with good retention of specific capacitance even up to 1000 charge-discharge cycles. The high specific capacitance and excellent cycle life of 5 vol.% PEG-intercalated Co(OH)(2) were attributed to the better electrode/electrolyte interaction due to well-defined nano-flake morphology.