Monday, 14 May 2018
Ballroom 6ABC (Washington State Convention Center)
Cobalt hydroxide (Co(OH)2) and nickel hydroxide (Ni(OH)2) which have optical band gap energies of 2.85 eV and 3.31 eV, respectively are used as active electrode materials for hybrid energy conversion and storage (HECS) cells by following the principle of the solid semiconductor/liquid junction photovoltaic effect. Interestingly, Co(OH)2 can absorb the visible light while Ni(OH)2 can absorb the ultraviolet (UV) light. The weight ratio of Co(OH)2-to-Ni(OH)2 was finely tuned and electrochemically investigated by cyclic voltammetry, galvanostatic charge discharge, and electrochemical impedance spectroscopy. Both ionic liquid and aqueous electrolytes were used. The in-situ X-ray absorption spectroscopy was intensively used to investigate the charge storage mechanism.