CA1142221A - Cadium compound additive for cells using divalent silver oxide - Google Patents
Cadium compound additive for cells using divalent silver oxideInfo
- Publication number
- CA1142221A CA1142221A CA000387245A CA387245A CA1142221A CA 1142221 A CA1142221 A CA 1142221A CA 000387245 A CA000387245 A CA 000387245A CA 387245 A CA387245 A CA 387245A CA 1142221 A CA1142221 A CA 1142221A
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- Prior art keywords
- silver oxide
- positive electrode
- cell
- oxide
- electrolyte
- Prior art date
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Abstract
CADMIUM COMPOUND ADDITIVE FOR
CELLS USING DIVALENT SILVER
OXIDE ELECTRODES
ABSTRACT OF THE INVENTION
An alkaline silver oxide cell having a negative electrode, an alkaline electrolyte and a positive electrode comprising a major amount of divalent silver oxide and wherein a minor amount of a cadmium compound, such as cadmium oxide, is incorporated into the electrolyte and/or positive electrode to improve the chemical stability of the divalent silver oxide in contact with the alkaline electrolyte.
S P E C I F I C A T I O N
1.
CELLS USING DIVALENT SILVER
OXIDE ELECTRODES
ABSTRACT OF THE INVENTION
An alkaline silver oxide cell having a negative electrode, an alkaline electrolyte and a positive electrode comprising a major amount of divalent silver oxide and wherein a minor amount of a cadmium compound, such as cadmium oxide, is incorporated into the electrolyte and/or positive electrode to improve the chemical stability of the divalent silver oxide in contact with the alkaline electrolyte.
S P E C I F I C A T I O N
1.
Description
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FIELD OF TH$ I~VENTIOW
The invention relates to a silver oxide alkaline cell employing a tivalent silver oxide containing positive electrode and wherein a minor amount of a cadmiu~ compound, such as cadmium oxide, is incorporated into the positive electrode and/or the electrolyte 80 as to improve the chemical stability of the divalent silver oxite in contact with the alkaline electrolyte. In addition, the cadmium compound can be em~loyed as an overbalance depolarizer in a divalent silver oxidetzinc/alkaline cell so as to substantially prevent hydrogen gassing from the cathode upon comple~e discharge of the cell.
BACKGROUND OF THE INVENTION
The battery has become a primary power source for many portable electronic devices such as radios, hearing aids, watches, calculators and the like. In order to maintain the overall electronic device as compact as possible the electronic devices are usually designed with cavities to accommodateminiature cells as their source of power, The cavities are usually made so that a cell can be snugly positioned therein thus making electronic contact with appropriate terminals within the device. A major potentiai problem in the use of a high energy density cell such as a divalent silver oxide/zinc/alkaline cell, is that if the cell b~lges, it usually becomes wedged within the cavity of the device which sometimes can result in damage to the device. In addition, when the cell bulges it may disturb the seal whereupon the electrolyte might escape to cause damage to the device and/or oxygen fro~ the atmosphere may enter which could cause wasteful corrosion of the anode.
~.
FIELD OF TH$ I~VENTIOW
The invention relates to a silver oxide alkaline cell employing a tivalent silver oxide containing positive electrode and wherein a minor amount of a cadmiu~ compound, such as cadmium oxide, is incorporated into the positive electrode and/or the electrolyte 80 as to improve the chemical stability of the divalent silver oxite in contact with the alkaline electrolyte. In addition, the cadmium compound can be em~loyed as an overbalance depolarizer in a divalent silver oxidetzinc/alkaline cell so as to substantially prevent hydrogen gassing from the cathode upon comple~e discharge of the cell.
BACKGROUND OF THE INVENTION
The battery has become a primary power source for many portable electronic devices such as radios, hearing aids, watches, calculators and the like. In order to maintain the overall electronic device as compact as possible the electronic devices are usually designed with cavities to accommodateminiature cells as their source of power, The cavities are usually made so that a cell can be snugly positioned therein thus making electronic contact with appropriate terminals within the device. A major potentiai problem in the use of a high energy density cell such as a divalent silver oxide/zinc/alkaline cell, is that if the cell b~lges, it usually becomes wedged within the cavity of the device which sometimes can result in damage to the device. In addition, when the cell bulges it may disturb the seal whereupon the electrolyte might escape to cause damage to the device and/or oxygen fro~ the atmosphere may enter which could cause wasteful corrosion of the anode.
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On the ~ther hand, if the ~eal of the c~ s ~aineained, high internal g~s pressure ~ay dcvelop which could cause not only bulging of the cell but evcn pocsible di~as~embIy of the cell Although divalent ilver oxide i6 a good high capacity po~eivc active material when u~ed $n alkaline c-lls, it is rather un~-ble when in contact with n aQueous alkaline elec-trolyte Specifically, div-lent ~ilver oxide ~s 8 highly oxi-dizlng material and s ~uch $t lc capable of decomposing the ~ater in n ~queous ~lk-line electrolyte thereby yielding oxy-gen gas In dd~tion, divalent ~ilver oxide will liberate oxy-gen when it deco~poses to form monovalent cil~er oxide when in eont-ct with ehe aqueous alkaline ~lectrolyte Divalent ~ilver oxide can also tt-ck cellulosic material~ ~n the cell, ~uch ~ the ~eparator, to fDrm c~rbonate ion at the expcnse of even morc electrol~te These re undesir-ble processes bcc-use they lead to bulging of the cell, deterioration of its parts and lo~s of ~ervice U S Patent 3,853,62~ discloses one ~pproach to ~tabilize divalent cilver oxide in cilver ox$de/zinc/ lkaline eell through the uoc of gold ions incorporated inro the alkaline ~lectroly~e on the positive cide of he cell'c separator or gold oxide ddet tO the pocitive active material of ene cell Canadian application serial no 323519 di6clo6es an alkaline silver oxide cell en~loying divalcnt ~llver oxide-containing electrode wherein an alum-inum additive ~c incorporated in the cell to improve the chemical ~tability of the divalent cilver oxide when in contact ~ .~
~ I
. .
-:~
-` 11426 1~42ZZl with the cell's slkaline electrolyte.
It is an obiect of the present invention to provide a divalent silver oxide cell thst will minimize internal gas pressure buildup so as to effectively eliminate distortion of the cell's housing.
It is another object of the present invention to provide a divalent silver oxide cell wherein a cadmium compound, such as cadmium oxide, is incorporated into the cell's electrolyte and/or the positive electrode so as to effectively control gas psessure buiLdup within the cell and thereby effecti~ely eliminate distortion of the cell's housing.
It is another object of the present invention to incorporate a ca~mium compound, such as eadmium oxide.in a tivalent silver oxide cell to chemically stabilize the tivalent silver oxite when in contact w~th the cell' 6 aqueous electrolyte.
It is another obiect of the present invention to incorporate a cadmium compound, such as cadmium oxide, in a divalent silver oxide/zinc cell as an overbalance depolarizer to effectively prevent hydrogen gassLng from the cathode upon complete discharge of the cell.
The foregoing and additional objects will become more fully apparent from the following description.
-SUMMARY OF THE I~VENTION
_ The invention relates to a silver oxide cell having a negative electrote, an aqueous alkaline electrolyte, a positive electrode comprising a m~jor portion of divalent . ,, . . ~
-~ 11426 :~4ZZ21 silver oxide and a separator between said negative and positive electrodes,the improvement comprising the incorporation of a minor amount of a cadmium compound, such as cadmium oxide, into the positive electrode and/or into the electrolyte of the cell to improve the stability of the divalent silver oxide-containing electrode in contact with the aqueous alkaline electrolyte.
As used herein, a positive electrode or a silver electrode shall mean an electrode wherein the active cathode material is divalent silver oxide (AgO) or an electrode wherein the major active material is divalent silver oxide in conjunction with an amount below 50% by weight of novalent silver oxide (Ag20) and/or some other electro-chemically active positive mæterial.
- The cadmium compound, such as cadmium oxide, may be addet in the solid positive electrode and/or dissolved in the electrolyte. The ca~mium compound added to the positiYe electrode may be either admixed with the divalent silver oxide or incorporated ~ithin the divalent silver oxide crystallites themselves through coprecipitation or absorption during synthesis, Atmixture of the cadmlum compount and tivalent silver ox~de material has the advantage of gseater flexibility in the choice of the divalent silver oxide material with regard to particle size, purity and the like.
The minor amount of the cadmium compound additive for use in the positive electrode of this invention to improve the stability of the divalent silver oxide when ~l~Z2Zl in contact with ~he cell's aqueous al~aline electrolyte should be between about 0~01 and abo~t 5 per cent based on the dry weight of the divalent silver oxide in the positive electrode and preferably between about 0.1 and about 0.3 weight per cent based on the dry weight of the divalent silver oxide in the positive electrote. ~n amount of the cadmium compount less than, for example, about O.Olweight per cent, would not provide sufficient material to effectively improve the stability of the tivalent silver oxide material when in contact with the aqueous alkaline electrolyte. An amount of the cadmium compound more than, for example, about 5 weight per cent àdted to the positive electrode would not further improve the stability of the divalent silver oxide wheh in contact with the aqueous alkaline electrolyte.
The catmium compound to be added to the electrolytè
in accordance with this invention shoult be added in an amount between about 0.0001 per cent and u~ to saturation af the cadmium compound in the electrolyte. For example, when using 8 33 per cent potassium hydroxide solution, the upper limit would ~e about 0.00125 per cent based on the weight of the electrolyte. An amount of the cadmium oxide less than, for example, about 0.0001 per cent would not provide sufficient material to effectively improve the stability of the divalent silver oxide material when in contact with the aqueous alkaline electrolyte.
In addition to its use as a stabilizing agent, cadmium oxide may also be used in larger amounts ranging 1~42ZZl from about 5 per cent to sbout 25 per cent by weight of the dry constituents of the positive electrode, as an overbalance depolarizer in a divalent silver oxide cell. An overbalance depolarizer is that part of the positive electrode in excess of the stoichiometric amount needed to balance the negative electrode. Its purpose is to augment the positive electrode capacity sufficiently to prevent hydrogen gassing from the cathode upon complete discharge of the cell (anote-limited).
Like tivalent silver oxide, a cadmium compount, such as cadmium oxide, has limited solubility in alkaline environments, discharges at a potential positive to hytrogen, and its volumetric energy tensity is sufficiently high so as not-to impair the over-all energy tensity of the ~ilver oxide/anote system. As an overbalance substitute for divaLent silver oxide, its advantages are that it is far less costly ant imp-rts chemical stability to the divalent silver oxide material when in contact with aqueous alkaline electrolyteO
It is also within the scope o:~ this invention to additionally add zinc oxite or aluminate ions to the elec-trolyte, ant/or zinc oxite or aluminum oxide to the positiveelectrote. The zinc oxide and aluminate ions can be adtet to the electrolyte in a range between about 0.5 and about 5 per cent baset on the weight of the electrolyte. When incorporated in the positive electrode, the zinc oxide and aluminum oxide can be atded in an amount between about 0.5 ant about 5 and about 0.001 and about O.l weight per cent, respectively, baset on the dry weight of the tivalent silver ~ 1 ~2 2 Zl 11426 oxite in the positive electrode. Zinc oxide has been found to be more desirable than aluminum oxide. Unexpectedly, the combination of cadmium oxide in the positive electrode and zinc oxide or aluminate ions in the electroLyte produced a synergistic effect the stability of divalent silver oxide in contact with the aqueous alkaline electrolyte.
It i9 also within the scope of this invention to additionally add a minor amount of a stabilizer, a flow agent and/or a lubricating sgent to the active positive mix to further alter the physical characteristics of the active positive mix for molding purposes to produce various size and type electrodes. Examples of some of these additives are ethylene bis-stearamite, zinc stearate, lead stearate, calcium stearate and the like, The silver oxide electrodes of this in~ention may be employet in an aqueous cell system using an anode such as zinc, cadmium, intium or the like. The electrode couple so selected can be employed with a compatible electrolyte and preferably an alkaline electrolyte, Examples of suitable electrolytes include aqueous solutions of alkaline earth metal hydroxides, such as strontium hytroxi~e and alkali metal hydroxides, exemplified by sotium hydroxide? potassium hydroxide, lithium hydroxite, rubidium hydroxide and cesium hydroxite. Compatible mixtures of the preceding may be utilized. Preferably, the electrode of this lnvention shoult be porous so that the walls of the pores and interstices of the electrode can become wetted by the electrolyte.
~l~Z221 EXAMPLE I
Several lots of test cells were produced each using a divalent silver oxide-containing positive pellet having a density of 90 grams per cubic inch, a negative electrode of zinc, and a 33% KOH electrolyte. The positive electrode was positioned in a cathode collector cup with a zinc screen disposed between the inner surface of the cup and the pos1tive pellet as disclosed in U. S. Patent No.
~
2~
On the ~ther hand, if the ~eal of the c~ s ~aineained, high internal g~s pressure ~ay dcvelop which could cause not only bulging of the cell but evcn pocsible di~as~embIy of the cell Although divalent ilver oxide i6 a good high capacity po~eivc active material when u~ed $n alkaline c-lls, it is rather un~-ble when in contact with n aQueous alkaline elec-trolyte Specifically, div-lent ~ilver oxide ~s 8 highly oxi-dizlng material and s ~uch $t lc capable of decomposing the ~ater in n ~queous ~lk-line electrolyte thereby yielding oxy-gen gas In dd~tion, divalent ~ilver oxide will liberate oxy-gen when it deco~poses to form monovalent cil~er oxide when in eont-ct with ehe aqueous alkaline ~lectrolyte Divalent ~ilver oxide can also tt-ck cellulosic material~ ~n the cell, ~uch ~ the ~eparator, to fDrm c~rbonate ion at the expcnse of even morc electrol~te These re undesir-ble processes bcc-use they lead to bulging of the cell, deterioration of its parts and lo~s of ~ervice U S Patent 3,853,62~ discloses one ~pproach to ~tabilize divalent cilver oxide in cilver ox$de/zinc/ lkaline eell through the uoc of gold ions incorporated inro the alkaline ~lectroly~e on the positive cide of he cell'c separator or gold oxide ddet tO the pocitive active material of ene cell Canadian application serial no 323519 di6clo6es an alkaline silver oxide cell en~loying divalcnt ~llver oxide-containing electrode wherein an alum-inum additive ~c incorporated in the cell to improve the chemical ~tability of the divalent cilver oxide when in contact ~ .~
~ I
. .
-:~
-` 11426 1~42ZZl with the cell's slkaline electrolyte.
It is an obiect of the present invention to provide a divalent silver oxide cell thst will minimize internal gas pressure buildup so as to effectively eliminate distortion of the cell's housing.
It is another object of the present invention to provide a divalent silver oxide cell wherein a cadmium compound, such as cadmium oxide, is incorporated into the cell's electrolyte and/or the positive electrode so as to effectively control gas psessure buiLdup within the cell and thereby effecti~ely eliminate distortion of the cell's housing.
It is another object of the present invention to incorporate a ca~mium compound, such as eadmium oxide.in a tivalent silver oxide cell to chemically stabilize the tivalent silver oxite when in contact w~th the cell' 6 aqueous electrolyte.
It is another obiect of the present invention to incorporate a cadmium compound, such as cadmium oxide, in a divalent silver oxide/zinc cell as an overbalance depolarizer to effectively prevent hydrogen gassLng from the cathode upon complete discharge of the cell.
The foregoing and additional objects will become more fully apparent from the following description.
-SUMMARY OF THE I~VENTION
_ The invention relates to a silver oxide cell having a negative electrote, an aqueous alkaline electrolyte, a positive electrode comprising a m~jor portion of divalent . ,, . . ~
-~ 11426 :~4ZZ21 silver oxide and a separator between said negative and positive electrodes,the improvement comprising the incorporation of a minor amount of a cadmium compound, such as cadmium oxide, into the positive electrode and/or into the electrolyte of the cell to improve the stability of the divalent silver oxide-containing electrode in contact with the aqueous alkaline electrolyte.
As used herein, a positive electrode or a silver electrode shall mean an electrode wherein the active cathode material is divalent silver oxide (AgO) or an electrode wherein the major active material is divalent silver oxide in conjunction with an amount below 50% by weight of novalent silver oxide (Ag20) and/or some other electro-chemically active positive mæterial.
- The cadmium compound, such as cadmium oxide, may be addet in the solid positive electrode and/or dissolved in the electrolyte. The ca~mium compound added to the positiYe electrode may be either admixed with the divalent silver oxide or incorporated ~ithin the divalent silver oxide crystallites themselves through coprecipitation or absorption during synthesis, Atmixture of the cadmlum compount and tivalent silver ox~de material has the advantage of gseater flexibility in the choice of the divalent silver oxide material with regard to particle size, purity and the like.
The minor amount of the cadmium compound additive for use in the positive electrode of this invention to improve the stability of the divalent silver oxide when ~l~Z2Zl in contact with ~he cell's aqueous al~aline electrolyte should be between about 0~01 and abo~t 5 per cent based on the dry weight of the divalent silver oxide in the positive electrode and preferably between about 0.1 and about 0.3 weight per cent based on the dry weight of the divalent silver oxide in the positive electrote. ~n amount of the cadmium compount less than, for example, about O.Olweight per cent, would not provide sufficient material to effectively improve the stability of the tivalent silver oxide material when in contact with the aqueous alkaline electrolyte. An amount of the cadmium compound more than, for example, about 5 weight per cent àdted to the positive electrode would not further improve the stability of the divalent silver oxide wheh in contact with the aqueous alkaline electrolyte.
The catmium compound to be added to the electrolytè
in accordance with this invention shoult be added in an amount between about 0.0001 per cent and u~ to saturation af the cadmium compound in the electrolyte. For example, when using 8 33 per cent potassium hydroxide solution, the upper limit would ~e about 0.00125 per cent based on the weight of the electrolyte. An amount of the cadmium oxide less than, for example, about 0.0001 per cent would not provide sufficient material to effectively improve the stability of the divalent silver oxide material when in contact with the aqueous alkaline electrolyte.
In addition to its use as a stabilizing agent, cadmium oxide may also be used in larger amounts ranging 1~42ZZl from about 5 per cent to sbout 25 per cent by weight of the dry constituents of the positive electrode, as an overbalance depolarizer in a divalent silver oxide cell. An overbalance depolarizer is that part of the positive electrode in excess of the stoichiometric amount needed to balance the negative electrode. Its purpose is to augment the positive electrode capacity sufficiently to prevent hydrogen gassing from the cathode upon complete discharge of the cell (anote-limited).
Like tivalent silver oxide, a cadmium compount, such as cadmium oxide, has limited solubility in alkaline environments, discharges at a potential positive to hytrogen, and its volumetric energy tensity is sufficiently high so as not-to impair the over-all energy tensity of the ~ilver oxide/anote system. As an overbalance substitute for divaLent silver oxide, its advantages are that it is far less costly ant imp-rts chemical stability to the divalent silver oxide material when in contact with aqueous alkaline electrolyteO
It is also within the scope o:~ this invention to additionally add zinc oxite or aluminate ions to the elec-trolyte, ant/or zinc oxite or aluminum oxide to the positiveelectrote. The zinc oxide and aluminate ions can be adtet to the electrolyte in a range between about 0.5 and about 5 per cent baset on the weight of the electrolyte. When incorporated in the positive electrode, the zinc oxide and aluminum oxide can be atded in an amount between about 0.5 ant about 5 and about 0.001 and about O.l weight per cent, respectively, baset on the dry weight of the tivalent silver ~ 1 ~2 2 Zl 11426 oxite in the positive electrode. Zinc oxide has been found to be more desirable than aluminum oxide. Unexpectedly, the combination of cadmium oxide in the positive electrode and zinc oxide or aluminate ions in the electroLyte produced a synergistic effect the stability of divalent silver oxide in contact with the aqueous alkaline electrolyte.
It i9 also within the scope of this invention to additionally add a minor amount of a stabilizer, a flow agent and/or a lubricating sgent to the active positive mix to further alter the physical characteristics of the active positive mix for molding purposes to produce various size and type electrodes. Examples of some of these additives are ethylene bis-stearamite, zinc stearate, lead stearate, calcium stearate and the like, The silver oxide electrodes of this in~ention may be employet in an aqueous cell system using an anode such as zinc, cadmium, intium or the like. The electrode couple so selected can be employed with a compatible electrolyte and preferably an alkaline electrolyte, Examples of suitable electrolytes include aqueous solutions of alkaline earth metal hydroxides, such as strontium hytroxi~e and alkali metal hydroxides, exemplified by sotium hydroxide? potassium hydroxide, lithium hydroxite, rubidium hydroxide and cesium hydroxite. Compatible mixtures of the preceding may be utilized. Preferably, the electrode of this lnvention shoult be porous so that the walls of the pores and interstices of the electrode can become wetted by the electrolyte.
~l~Z221 EXAMPLE I
Several lots of test cells were produced each using a divalent silver oxide-containing positive pellet having a density of 90 grams per cubic inch, a negative electrode of zinc, and a 33% KOH electrolyte. The positive electrode was positioned in a cathode collector cup with a zinc screen disposed between the inner surface of the cup and the pos1tive pellet as disclosed in U. S. Patent No.
3,920,478. Next~a dual separator consisting of cellulosic barrier film and an absorbent layer, ha~ing a gold layer on that side adjacent the cathode, was disposed on top of the positive pellet followed by the zinc electrode. An anode cup containing the zinc electrode was then placed over the cathode cup and sealet thereto in a conventional manner.
The exact const~tuents of the positive electrode and any additives to the electrolyte are shown in Table 1.
The cells were stored for three months under various temperature conditions. Thereafter the cells were measured for any bulging and the results obtained for each test lot were averaget and are shown in Table 2 along with the maximum cell bulge observed in each lot. In addition, the service life to a 1.3 volt cutoff was observed and is al~o shown in Table 2.
~1~2221 :' Q O o o O o o aJ
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;Z21 The results of the data shc>wn in Table 2 illustrate that u~ing the teachings of this invention, a cadmium compous~d additive with or without zinc oxide and aluminum additives can be effectively u~ed to stabilize divalent silver oxide when in contact with an aqueous alkaline electrolyte 80 as to reduce cell bulging. As also illustrated, the combination of a cadmium com-pound in the positive electrode and zinc oxide or aluminate ions in the electrolyte produced a synergistic effect on the stability of divalont oilver oxide in contact with aqueous alkaline electrolyte.
That i8, the addition of both a cadmium compound in the positive electrode and zinc oxide or aluminate ion~ to the electrolyte reduced bulge more than the composite of either material acting alone This i~ ~hown for example by comparing te~t Lot 23 with Lota 16, 17, and 19 for ZnO addition to the eloctrolyte, and by comparing Lot ZZ
with Lots 16, 18, and 19 for aluminate addition to the electrolyte.
EXAMPLE II
Several test lots of cell~ were produced as de~cribed in Example I except that the cathode and electrolyte compositions employed are a~ shown in Table 3. The result~ of the data shown in TaWe 3 illu~trate the benefits as expressed above in Example I in that the cadmium compound adtitive reduces cell bulging. Both Example I
and Example II show that the addition of the cadmium compound by admixture gives olightly better bulge control than by coprecipitation.
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The exact const~tuents of the positive electrode and any additives to the electrolyte are shown in Table 1.
The cells were stored for three months under various temperature conditions. Thereafter the cells were measured for any bulging and the results obtained for each test lot were averaget and are shown in Table 2 along with the maximum cell bulge observed in each lot. In addition, the service life to a 1.3 volt cutoff was observed and is al~o shown in Table 2.
~1~2221 :' Q O o o O o o aJ
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O
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.
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~ ~ ~ ~ i ~ ~
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.
;Z21 The results of the data shc>wn in Table 2 illustrate that u~ing the teachings of this invention, a cadmium compous~d additive with or without zinc oxide and aluminum additives can be effectively u~ed to stabilize divalent silver oxide when in contact with an aqueous alkaline electrolyte 80 as to reduce cell bulging. As also illustrated, the combination of a cadmium com-pound in the positive electrode and zinc oxide or aluminate ions in the electrolyte produced a synergistic effect on the stability of divalont oilver oxide in contact with aqueous alkaline electrolyte.
That i8, the addition of both a cadmium compound in the positive electrode and zinc oxide or aluminate ion~ to the electrolyte reduced bulge more than the composite of either material acting alone This i~ ~hown for example by comparing te~t Lot 23 with Lota 16, 17, and 19 for ZnO addition to the eloctrolyte, and by comparing Lot ZZ
with Lots 16, 18, and 19 for aluminate addition to the electrolyte.
EXAMPLE II
Several test lots of cell~ were produced as de~cribed in Example I except that the cathode and electrolyte compositions employed are a~ shown in Table 3. The result~ of the data shown in TaWe 3 illu~trate the benefits as expressed above in Example I in that the cadmium compound adtitive reduces cell bulging. Both Example I
and Example II show that the addition of the cadmium compound by admixture gives olightly better bulge control than by coprecipitation.
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Claims (13)
1. A silver oxide cell having a negative electrode, an aqueous alkaline electrolyte, a positive electrode comprising a major portion of divalent silver oxide and a separator between said negative electrode and the positive electrode, the improvement comprising the incorporation of cadmium oxide into the electrolyte to improve the stability of the divalent silver oxide-containing electrode in contact with the aqueous alkaline electrolyte, said cadmium oxide being present in the electrolyte between about 0.0001 weight per cent based on the weight of the electro-lyte up to saturation of the cadmium oxide in the electrolyte.
2. The silver oxide cell of claim 1 wherein the positive electrode contains less than 50 per cent by weight of monovalent silver oxide based on the dry weight of the divalent silver oxide in the positive electrode.
3. The silver oxide cell of claim 1 wherein the aqueous alkaline electrolyte contains a minor amount of zinc oxide or aluminate ions.
4. The silver oxide cell of claim 1 wherein the negative electrode is selected from the group consisting of zinc, cadmium and indium.
5. The silver oxide cell of claim 1 wherein the negative electrode is zinc.
6. The silver oxide cell of claim 1 wherein the negative electrode is zinc and the electrolyte comprises aqueous potassium hydroxide or sodium hdyroxide.
7. The silver oxide cell of claim 1 wherein the positive electrode contains a minor amount of cadmium oxide.
16.
16.
8. The silver oxide cell of claim 7 wherein the cadmium oxide is present in the positive electrode in an amount between about 0.01 and 0.5 weight per cent based on the dry weight of the divalent silver oxide in the positive electrode.
9. The silver oxide cell of claim 8 wherein the positive electrode contains less than 50 per cent by weight of monovalent silver oxide based on the weight of the dry constituents of the positive electrode.
10. The silver oxide cell of claim 9 wherein the cadmium oxide is present in the positive electrode in an amount between about 0.01 and 0.5 weight per cent based on the dry weight of the divalent silver oxide in the positive electrode.
11. The silver oxide cell of claim 7 wherein the positive electrode contains a minor amount of a material selected from the group consisting of ethylene bis-stearamide, zinc stearate, lead stearate and calcium stearate.
12. The silver oxide cell of claim 7 wherein the negative electrode is selected from the group consisting of zinc, cadmium and indium.
13. The silver oxide cell of claim 8 wherein the negative electrode is zinc and the electrolyte comprises aqueous potassium hydroxide or sodium hydroxide.
17.
17.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000387245A CA1142221A (en) | 1979-02-28 | 1981-10-02 | Cadium compound additive for cells using divalent silver oxide |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA322,622A CA1128121A (en) | 1978-03-30 | 1979-02-28 | Cadium compound additive for cells using divalent silver oxide |
| CA000387245A CA1142221A (en) | 1979-02-28 | 1981-10-02 | Cadium compound additive for cells using divalent silver oxide |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1142221A true CA1142221A (en) | 1983-03-01 |
Family
ID=25668887
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000387245A Expired CA1142221A (en) | 1979-02-28 | 1981-10-02 | Cadium compound additive for cells using divalent silver oxide |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1142221A (en) |
-
1981
- 1981-10-02 CA CA000387245A patent/CA1142221A/en not_active Expired
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