Non-sintered nickel electrode for an alkaline electrolyte secondary electrochemical cell

DETAILED DESCRIPTION OF THE INVENTION Other features and advantages of the present invention will become apparent on reading the following description of embodiments of the invention which is given by way of illustrative and non-limiting example only.
EXAMPLE 1 (comparative) 1i) Standard cobalt hydroxide Co(OH).
sub.
2 was prepared in the following manner.
0.
5 liter of a 1M aqueous solution of cobalt sulfate was introduced into a precipitation reactor maintained at a constant temperature of 50.
degree.
C.
Synthesis was performed in an inert atmosphere with the aim of preventing all contact with oxygen in order to reduce the risk of oxidation of the cobalt hydroxide to be produced.
650 g of 2M sodium hydroxide solution was added continuously and at a constant flowrate for 30 minutes.
On completion of the addition of the sodium hydroxide, the solution was constantly stirred and heated for 2 hours to allow the hydroxide particles to mature.
The precipitate obtained was then filtered and washed with distilled water at room temperature in an inert atmosphere.
The substance obtained was then dried in a vacuum for 24 hours at a temperature of 70.
degree.
C.
, after flooding the oven with inert gas.
The precipitate obtained was then ground in an inert atmosphere to the appropriate particle size range.
1ii) "Test" cobalt electrodes "a" were made using the above cobalt hydroxide powder in the form of a paste whose composition expressed as a percentage by weight relative to the weight of the paste was approximately as follows: cobalt hydroxide powder: 22%, water: 76.
2%, CMC: 0.
3%, PTFE: 1.
5%.
The resulting paste was introduced into nickel foam having a porosity of approximately 95%.
The result was dried and then rolled to obtain the electrodes "a".
1iii) Cobalt-cadmium Co--Cd storage cells were assembled incorporating the electrodes "a".
Each positive electrode was placed in contact with two super-capacitive cadmium negative electrodes.
The positive and negative electrodes were separated by a layer of non-woven polypropylene