| abstract |
An energy storage device has a nickel-based positive electrode, a carbon-based negative electrode, a separator, and an aqueous electrolyte. The positive electrode comprises from 3% to 95% by weight of nickel hydroxide, with the balance being chosen from the group consisting of: nickel powder, cobalt powder, carbon powder, and mixtures thereof. The negative electrode comprises from 10% to 95% by weight of carbon, with the balance being at least one redox couple. The electrolyte is an aqueous alkaline solution, and the separator is chosen from the group consisting of: non-woven nylon separator material, microporous polypropylene, microporous polyethylene, and combinations and mixtures thereof. Typically, the redox couple is chosen from the group of active redox couples which include, as their active material, bismuth oxide, indium oxide, cobalt oxide, iron oxide, iron hydroxide, hydrides of metals from the Groups IIIA, IIIB, IVA, IVB, VB, VIB, VIIB, and VIII, of the Periodic Table, hydrides of mischmetals, oxides of mischmetals, and combinations thereof. |