The pseudocapacitance and morphology of an electrodeposited cobalt hydroxide (Co(OH)2) significantly depends on the architecture of the electrode substrate. The nano-porous Ni framework, derived from the selective dissolution of Cu from a Ni-Cu alloy, effectively promotes the electrochemical utilization of deposited Co(OH)2 even at a high loading amount condition. The great electronic and ionic conduction within the nano-structured electrode improves the energy storage performance of Co(OH)2 as compared to that for a conventional flat Ni substrate. In this work, the Co(OH)2 mass specific capacitance, evaluated using cyclic voltammetry (CV), only slightly decreases from 2650 to 2470 F g-1 when the potential sweep rate is substantially increased from 5 to 200 mV s-1. The developed Ni(OH)2/NiOOH (from the nano-porous framework) incorporates with the deposited Co(OH)2 upon CV cycling; the mixed hydroxide shows a noticeably synergistic capacitance. Furthermore, the dissolution of Co(OH)2 in KOH electrolyte is greatly suppressed due to the incorporation of Ni(OH)2/NiOOH, consequently prolonging the electrode cycle life.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering