Including didymium hydrate in nickel hydroxide of positive electrode of storage batteries to increase ampere hour capacit

Carson, W. N., Jr.

English

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5 
Metal 
I,aatile.lunl .................. 
Nci!iyrnium ................................. 
Sa*i?.iri,im.. ............................ 
(Ja:ioiiii:iin ................................. 
Ytt,riiiin ........................... 
Other  rare enrth's oviiirs ............................ 
Foreigii rnctal Ca. Fe. etc. oxides.- 
cadmium capacity is built into the cell. 
vide a nickel hydroxide electrode of greatly improved 
capacity. Corium ..................................... 
electrode of substantial ampere hour capacity. 
The principal object of the present invention is to pro- 
Another object is to provide a thin nickel hydroxide 45 Praqcodvniiini ............................. 
Still another object of the persent invention is to pro- 
vide a simplified technique for forming nickel hydroxide 
electrodes. 
Oxide Percent 
____ ___ 
I , ~ , ' I ~ .  .... 16. 9 
f ' v :  )*.-. .... 0. 5 
I'rq 11 I... .. a. 5 
Nd203 .. i 2. $1 
2 n  S ~ M  ~ 3 .  . ' 
c ; d z ' i ~  .. I 1 3 
y2 i t .  . . . .  1 ri 2 , 0 5  
1 .................... 2. 4 
https://ntrs.nasa.gov/search.jsp?R=19710001134 2020-03-17T02:27:31+00:00Z
3,311,602 
acid prediluted in a 1: 1 ratio with water. Then the re- 
sulting solution of didymium nitrate is mixed with 1310 
grams of nickel nitrate hexahydrate, 3 grams of 80% 
nitric acid, and sufficient distilled water to form one liter 
of the nitrate solution. Several standard (SAFT-VO 
plaques) sintered nickel plaques 1%" x 2%" having a 
porosity of about 80% are placed into a suitable holder 
and the assembled plaques heated to 65-70" C. under 
vacuum. Thereafter the above nitrate solution (65-70" 
C.) is drawn down into the holder and allowed to remain 
in contact with the nickel plaques for about five minutcs. 
At the end of this soaking period the nitrate solution is 
removed rind the wet electrodes dricd for twcnty to thirty 
minutes at 60-70" C.; thercaftcr the electrodes arc im- 
mcrsed in a large exccss of aqueous (25%) sodium hy- 
droxidc solution. The caustic treatment serves to con- 
vert the nitrate salts retained in the sintered nickel 
plaques to the insoluble hydroxide hydrate. Thereafter 
the electrodes are water washed several times in distilled 
water and electro-chemically cleaned to remove residual 
nitrate ions; following with thorough washing with dis- 
tilled water and air drying at room temperature com- 
pletes the electrode fabrication process. The electro- 
chemical cleaning treatment was electrolysis at one am- 
pere for four hours in 26% sodium hydroxide followed 
by a repeat of the same treatment in fresh sodium hy- 
droxide solution. 
The impregnated nickel hydroxide electrodes are as- 
sembled into cells with cadmium electrodes of standard 
(7-time) impregnation and a 3 1 % aqueous potassium 
hydroxide electrolyte added. A charging current of 100 
milliamperes is applied for 16 hours. Then the cells are 
discharged at the same current for 8 hours. Further test- 
ing of the didymium activated nickel hydroxide electrodes 
was accomplished by cycling the cells at 100 milliamperes 
for ten cycles. 
The degree of utilization, Le., the number of ampere 
hours developed for the cells containing a didymium 
activated nickel hydroxide electrode was about 2.1. The 
theoretical maximum is 1.0; and cells with control nickel 
hydroxide electrodes comparably prepared with a pure 
nickel hydroxide impregnant attained 0.8 1. Similar tests 
substituting other additive materials such as platinum, 
scandium, gallium, aluminum, indium, ytterbium, and 
many others all failed to show any improvement com- 
parable to that of the didymium activated nickel hydrox- 
ide electrode. In fact many of the other materials re- 
sulted in electrodes with a percent utilization consider- 
ably below that of the control electrode. Further tests 
on the cells with didymiu activated nickel hydroxide 
electrodes showed that the charge $(0.490) and the volt- 
age at  midpoint of the discharge q c l e  (0.380) was not 
materially affected, being about the same as the values 
6 exhibited by the cells with control electrodes and with 
most of the nickel hydroxide electrodes containing other 
additives. 
Example II  
Didymium hydrate from a second source was con- 
10 verted to the dissolved nitrate and substituted for ten 
mole percent of the nickel in forming a 5 molar metal 
nitrate impregnating solution. The nickel hydroxide 
electrodes were formed according to the proccdure of 
Example I. 
This time the test cells were tested at 5O-milliamprc 
charge and discharge. The test results were quite con- 
sistent with the results obtained in Example I. However, 
the utilization factor climbed to 2.62 with again com- 
2o parable charge (0.475) and midpoint values (0.360) for 
the cells containing a didymium activated nickel hydrox- 
ide electrode as compared to cells with both control elec- 
trode and electrodes doped with other materials. 
Since different embodiments 
26 may be made without departibg 
thereof, it should be appreciated 
limited to the above disclosed 
except insofar as specified in the 
in combination therewith comprises the positive elec- 
hydroxide and from 
droxide of didymium 
*' 
What is claimed i w  . 
3o I. A nickel-cadmium battery 
UNITED STATES PATENTS 
46 2,634,303 4/1953 Moulton. 
2,771,499 11/1956 Fleischer. 
3,066,178 11/1962 Winkler. 
60 A. SKAPARS, Assistant Examiner. 
WINSTON A. DOUGLAS, Primary Examirrer. 


Didymium hydrate additive to nickel hydroxide electrodes Patent

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