Electrochemically active material for the negative electrode of a secondary electrochemical cell having an alkaline electrolyte
AssigneeAlcatel
InventorsPatrick Bernard, Lionel Goubault, Laure Le Guenne
Life of this patent
Estimating the term…
Abstract
The present invention provides an electrochemically active material comprising a hydridable alloy whose surface is covered in a protective layer constituted mainly by a nickel hydroxide. The layer is preferably constituted by at least 80% by weight of nickel hydroxide and includes up to 20% by weight of at least one other metal which may be taken from Mn, Al, Co, Cr, Fe, and Cu. Also preferably, the layer represents 1% to 4% by weight of the hydridable alloy.
Claims23
An electrochemically active material comprising a hydridable alloy whose surface is covered in a protective layer, wherein said layer is constituted mainly by a nickel hydroxide.
A negative electrode for a secondary electrochemical cell having an alkaline electrolyte, the electrode containing an electrochemically active material comprising a hydridable alloy whose surface is covered in a protective layer, constituted mainly by a nickel hydroxide.
A secondary electrochemical cell having a negative electrode containing an electrochemically active material comprising a hydridable alloy whose surface is covered in a protective layer constituted mainly by a nickel hydroxide.
A method of fabricating an electrochemically active material comprising a hydridable alloy whose surface is covered in a protective layer constituted mainly by a nickel hydroxide, the method comprising the following steps:
- suspending the hydridable alloy powder in water;
- adding an aqueous solution of a nickel salt to said suspension;
- then adding an alkaline solution so as to bring the pH to a value of not less than 7;
- leaving said powder in contact with said alkaline solution;
- and
- separating, washing, and drying said resulting active material powder.
A method of fabricating an electrochemically active material comprising a hydridable alloy whose surface is covered in a protective layer constituted mainly by a nickel hydroxide, the method comprising the following steps:
- suspending the hydridable alloy powder in an acid aqueous solution in order to eliminate the oxide layer;
- filtering and washing the deoxidized hydridable alloy powder, and then putting it into suspension in water;
- adding an aqueous solution of a nickel salt to the suspension;
- then adding an alkaline solution so as to bring the pH to a value of not less than 7;
- leaving the powder in contact with the alkaline solution;
- and
- separating, washing, and drying the resulting active material powder.
Dependencies are inferred from the claim text.