Synthesis, characterization and improvement of α-Co(OH)2 for supercapacitor applications

In the present study, α-Co(OH)2 was prepared by a potentiostatic deposition process at -1.0V (vs. Ag/AgCl) onto a nickel electrode by using a aqueous solution of 0.1 M Co(NO3)2. The structure and surface morphology of the obtained the α-Co(OH)2 were studied by using X-ray diffraction analysis and scanning electron microscopy. XRD data and the scanning electron microscopy images showed that the as-deposited films have an interlaced nanosheet-like surface morphology and possess a regular nanostructure with hexagonal arrays of pores of nanometer dimension and extended periodicity The capacitive characteristics of the α-Co(OH)2 electrodes were investigated by means of cyclic voltammetry and constant current charge-discharge cycling in 1 M KOH electrolyte with and without addition of 0.05% Triton X-100. Galvanostatic charge-discharge curves showed that the capacitance was increased from 720 F g-1 to 804 F g-1 and the capacitance retention from 63% to 76% after 500 charge/discharge cycles by addition of 0.05% Triton X-100 surface active materials to 1M KOH electrolyte solution. This indicates that the surfactant addition is a promising process for increasing capacitance of the α-Co(OH)2 electrodes.