A novel asymmetric capacitor based on Co(OH)2/USY composite and activated carbon electrodes

A new hybrid electrochemical capacitor has been successfully designed by using Co(OH)2/USY composite and active carbon (AC) as positive and negative electrode, respectively. The Co(OH)2/USY composite material is cobalt hydroxide loaded on ultra-stable Y zeolite (designated Co(OH)2/USY) through self-directed growth process. The Co(OH)2/USY and AC electrodes were individually tested in 1 M KOH aqueous electrolyte in order to define the adequate balance of active materials in the capacitor as well as the working voltage. To fabricate the hybrid cell systems, it achieved the maximum capacitive performance of 110 F/g, which is the highest value compared with the other similar metal oxide in AC hybrid capacitor systems in the same medium. Also it was found that the asymmetric cell worked in the larger voltage range and exhibited higher energy and power characteristics. The notable improved electrochemical performances strongly suggest that the hybrid cell can be a promising capacitor devices applied for the energy storage.