Inorganic additives for zinc-alkaline secondary batteries and alkaline zinc-plating baths
AssigneesState of Israel, Ministry of Industry, Commerce and Tourism, National Physical Laboratory of Israel, The Scientific Research Foundation
InventorsYitzchak Klein, Jonathan G. Goldstein
Life of this patent
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Abstract
The invention relates to an additive, to be added to conventional electrolytes of alkaline secondary zinc cells or to alkaline zinc plating baths, adapted to establish in said liquids a minimum concentration of 10.sup.-6 M per liter of cobalt ions and a minimum concentration of 5.10.sup.-6 M per liter of cadmium ions, said additive being a coprecipitate of cobalt hydroxide and cadmium hydroxide and either magnesium hydroxide or calcium hydroxide, to electrolytes for alkaline secondary zinc cells and alkaline zinc plating baths containing such additives and to a process for the production of such additives.
Claims15
An additive, to be added to conventional electrolytes of alkaline secondary zinc cells or to alkaline zinc plating baths adapted to establish in said liquids a minimum concentrate of 10.sup.-6 M per liter of cobalt ions and a minimum concentration of 5.10.sup.-6 M per liter of cadmium ions being a coprecipitated hydroxide gel of cobalt hydroxide and of cadmium hydroxide and with at least one of magnesium hydroxide and calcium hydroxide.
Additives to be added to conventional electrolytes of alkaline secondary zinc cells or to alkaline zinc plating baths, adapted to establish a steady-state minimum concentration of at least 10.sup.-6 M Co-ions and 5.10.sup.-6 M Cd-ions, in combination with Mg or Ca-ions, said additive being a mixture of very sparingly soluble compounds of the required metals in the form of a coprecipitate consisting mainly of hydroxides of the metals in gel form.
A process for the production of additives for use in electrolytes of secondary alkaline zinc cells and for use in electroplating baths for electroplating with zinc, which comprises preparing a solution of water-soluble salts of cobalt and cadmium and of magnesium or calcium;
- precipitating a coprecipitate gel of the hydroxides of same by adding to said solution an aqueous solution of an alkali metal hydroxide until a hydroxide gel precipitate is obtained;
- separating the precipitate and removing from same soluble impurities by washing with water.
Dependencies are inferred from the claim text.