CA1111494A - Molded metal oxide electrodes containing an ethylene acrylic acid additive - Google Patents
Molded metal oxide electrodes containing an ethylene acrylic acid additiveInfo
- Publication number
- CA1111494A CA1111494A CA322,242A CA322242A CA1111494A CA 1111494 A CA1111494 A CA 1111494A CA 322242 A CA322242 A CA 322242A CA 1111494 A CA1111494 A CA 1111494A
- Authority
- CA
- Canada
- Prior art keywords
- metal oxide
- silver oxide
- electrode
- acrylic acid
- weight
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/06—Electrodes for primary cells
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Primary Cells (AREA)
Abstract
MOLDED METAL OXIDE ELECTRODES
CONTAINING AN ETHYLENE ACRYLIC ACID ADDITIVE
ABSTRACT OF THE DISCLOSURE
A method for producing a molded metal oxide electrode such as a silver oxide electrode and the electrode so produced for use in electrochemical cells, such as alkaline-zinc cells, which comprises a metal oxide and a minor amount of an ethylene acrylic acid polymer.
S P E C I F I C A T I O N
1.
CONTAINING AN ETHYLENE ACRYLIC ACID ADDITIVE
ABSTRACT OF THE DISCLOSURE
A method for producing a molded metal oxide electrode such as a silver oxide electrode and the electrode so produced for use in electrochemical cells, such as alkaline-zinc cells, which comprises a metal oxide and a minor amount of an ethylene acrylic acid polymer.
S P E C I F I C A T I O N
1.
Description
Field of the In~ention The invention relates to a method for producing a molded metal oxide electrode and the molded electrode so produced for use in electrochemical cells which com-prises a metal oxide, such as silver oxide, and an amount of an ethylene acrylic acid polymer preferably between about 0.5 and 10 weight per cent of the dry powder con-stituents of the metal oxide e~ectrode.
Back~round of the Invention Miniature button alkaline metal oxide cells, such as alkaline silver oxide cells, have gained wide commercial acceptance for many applications because they are characterized as being high capacity, small volume electric cells. ~n other words, they have a high power output and energy per unit weight and unit volume of active cathode material. One of the major disadvantages of divalent silver oxide cells is that they discharge at two successive different potentials. This is due to the fact that the active materials of such cells are first divalent silver oxide (AgO) which is then reduced to monovalent silver oxide (Ag20)~ Silver oxide cells using monovalent silver oxide as the only active cathode material will have a theoretical unipotential discharge at about 1.57 volts but the capacity in milliampere hours per gram of monovalent silver oxide is substantially lower than the capacity with divalent silver oxide. On the other hand, silver oxide button cells [0.455 inch (1.16 cm diameter) ~111494 by 0.210 inch (0.533 cm high)] using only divalent silver oxide as the starting active cathode material w;ll dis-charge at a first potential at about 1.7 volts across a 300-ohm resistor for the first 40 hours of discharge, for example, and then drop to approxim~tely 1.5 volts for the balance of the useful discharge life. Thus, mono-valent silver oxide cells having the advantage of dis-charging at a single unipotential plateau but with some sacrifice in capacity as compared with divalent silver oxide cells which have the advantage of having a much higher capacity but with the disadvan~age of discharging at two successive distinct voltage plateaus. Divalent silver oxide has about 1.9 times more capacity per gram than monovalent silver oxide and about 2 times more capacity per unit volume than novalent silver oxide.
Many cell or battery applications, particularly in transistorized devices such as hearing aids, watches, cal-culators and the like, require an essentially unipotential d~scharge source for proper operation and, therefore, cannot effectively use the dual voltage level discharge which is normally characteristic of divalent silver oxide cells.
Consequently, many methods have been proposed for obtaining a unipotential discharge from a divalent silver oxide cell without undue sacrifice in capacity.
One method disclosed in U.S. Patents 3,615,858 and 3,655,450 entails providing a continuous layer of mono-valent silver oxide in physical and electrical contact with a divalent silver oxide pellet. During assembly ~111494 of the cell, the cathode pellet is disposed against the inner surface of a cathode cup or collector whereupon the layer of monovalent silver oxide physically isolates the tivalent silver oxide from contact with the cathode cup so that the sole electronic path for discharge of the divalent silver oxide is through the monovalent silver oxide layer.
In U. S. Patent 3,476,610 a silver oxide battery is disclosed which employs a positive electrode c prised mainly of divalent silver oxide with the addition of monovalent silver oxide present in part as an electrolyte-impermeable masking layer. This layer isolates the divalent ailver oxide from contact with the electrolyte of the battery until discharge begins whereupon the monovalent silver oxide becomes electrolyte-permeable.
When this occurq, the electrolyte then begins to contact the divalent silver oxide. In addition, the monovalent silver oxide i~ also present as an interposed layer between the divalent silver oxide and the inner surface of the cathode cup or collector 80 as to isolate the divalent silver oxide from electronic contact with said cathode cup which is the positive terminal of the cell.
In U. S. Patent 3,484,295 a silver oxide battery is disclosed which utilizes a positive silver electrode comprising divalent silver oxide and monovalent silver oxide. The latter oxide is employed as an electrolyte-impermeable layer which is interposed between ~111494 the divalent silver oxide and the battery components containing the electrolyte so as to isolate the divalent silver oxide from contact with the electrolyte until the monovalent silver material is discharged. If the discharge product of the monovalent silver material is continually reoxidized by the divalent silver material in the presence of the battery electrolyte, then it is possible that the battery will yield a unipotential discharge.
In U. S. Patent 3,920,478 a silver oxide cell is disclosed which employs a positive electrode comprising divalent silver oxide housed in a positive cathode con-tainer, and interposed between the positive electrode and the inner wall of the cathode container and/or between the positive electrode and the separator is a discontinuous oxidizable metal, such as a zinc screen, which functions to reduce a portion of the divalent silver oxide to mono-valent silver oxide which isolates the divalent silver oxide portion of the positive electrode from the container . 20 90 as to produce a unipotential discharge on low drain conditions.
In U. S. Patent 3,925,102 a silver oxide cell is disclosed which employ~ a positive electrode comprising divalent silver oxide housed in a positive electrode container having an upstanding wall and a closed end.
Interposed between the positive electrode ant the inner upstanding wall is an oxidizable zinc ring which functions to reduce a portion of the divalent silver oxide to mono-valent silver oxide which isolates the divalent silver oxide portion of the positive electrode from the ccntainer so as to produce a unipotential discharge on low drain conditions.
The silver oxide electrodes for use in the above-described cells are generally molded into inflexible pellet-type solid electrodes with the aid of a lubricant. The presence of many of the conventional lubricants, such as graphite, in molded silver oxide electrodes containing divalent silver oxide has been found to adversely affect the shelf life of the cells employing such electrodes and/or the unipotential discharge characteristic of the cells.
Accordingly, it is an object of the present inven-tion to provide a metal oxide electrode for electrochemical cells which comprises a metal oxide and a minor amount of solid~ethylene acrylic acid poly~er.
Another ob;ect of this invention is to provide a silver oxide electrode for electrochemical cells which com-prises divalent silver oxide and a minor amount of an 2Q ethylene acrylic acid polymer.
Another object of this invention is to incorporate a minor amount of an ethylene acrylic acid polymer into a divalent silver oxide-containing material so as to provide lubricity and cohesion to the mixture so that said mixture can be easily molded into a substantially cohesive inflexible body which can be easily handled.
Another ob;ect of this invention is to provide a porous positive electrode for silver oxide cells which comprises divalent silver oxide and a minor amount of an ethylene acrylic acid polymer ancl which electrode will exhibit good electrolyte absorption characteristics.
Another object of this invention is to provide a method for producing a molded metal oxide electrode.
Summary of the Invention The invention relates to a molded metal oxide electrode, such as a silver oxide electrode, for use in electrochemical cells which comprises a metal oxide, such as divalent silver oxide, and a minor amount of an ethylene acrylic acid polymer, for example, between about 0.5 and about 10 weight per cent,preferably between about 1.0 and about
Back~round of the Invention Miniature button alkaline metal oxide cells, such as alkaline silver oxide cells, have gained wide commercial acceptance for many applications because they are characterized as being high capacity, small volume electric cells. ~n other words, they have a high power output and energy per unit weight and unit volume of active cathode material. One of the major disadvantages of divalent silver oxide cells is that they discharge at two successive different potentials. This is due to the fact that the active materials of such cells are first divalent silver oxide (AgO) which is then reduced to monovalent silver oxide (Ag20)~ Silver oxide cells using monovalent silver oxide as the only active cathode material will have a theoretical unipotential discharge at about 1.57 volts but the capacity in milliampere hours per gram of monovalent silver oxide is substantially lower than the capacity with divalent silver oxide. On the other hand, silver oxide button cells [0.455 inch (1.16 cm diameter) ~111494 by 0.210 inch (0.533 cm high)] using only divalent silver oxide as the starting active cathode material w;ll dis-charge at a first potential at about 1.7 volts across a 300-ohm resistor for the first 40 hours of discharge, for example, and then drop to approxim~tely 1.5 volts for the balance of the useful discharge life. Thus, mono-valent silver oxide cells having the advantage of dis-charging at a single unipotential plateau but with some sacrifice in capacity as compared with divalent silver oxide cells which have the advantage of having a much higher capacity but with the disadvan~age of discharging at two successive distinct voltage plateaus. Divalent silver oxide has about 1.9 times more capacity per gram than monovalent silver oxide and about 2 times more capacity per unit volume than novalent silver oxide.
Many cell or battery applications, particularly in transistorized devices such as hearing aids, watches, cal-culators and the like, require an essentially unipotential d~scharge source for proper operation and, therefore, cannot effectively use the dual voltage level discharge which is normally characteristic of divalent silver oxide cells.
Consequently, many methods have been proposed for obtaining a unipotential discharge from a divalent silver oxide cell without undue sacrifice in capacity.
One method disclosed in U.S. Patents 3,615,858 and 3,655,450 entails providing a continuous layer of mono-valent silver oxide in physical and electrical contact with a divalent silver oxide pellet. During assembly ~111494 of the cell, the cathode pellet is disposed against the inner surface of a cathode cup or collector whereupon the layer of monovalent silver oxide physically isolates the tivalent silver oxide from contact with the cathode cup so that the sole electronic path for discharge of the divalent silver oxide is through the monovalent silver oxide layer.
In U. S. Patent 3,476,610 a silver oxide battery is disclosed which employs a positive electrode c prised mainly of divalent silver oxide with the addition of monovalent silver oxide present in part as an electrolyte-impermeable masking layer. This layer isolates the divalent ailver oxide from contact with the electrolyte of the battery until discharge begins whereupon the monovalent silver oxide becomes electrolyte-permeable.
When this occurq, the electrolyte then begins to contact the divalent silver oxide. In addition, the monovalent silver oxide i~ also present as an interposed layer between the divalent silver oxide and the inner surface of the cathode cup or collector 80 as to isolate the divalent silver oxide from electronic contact with said cathode cup which is the positive terminal of the cell.
In U. S. Patent 3,484,295 a silver oxide battery is disclosed which utilizes a positive silver electrode comprising divalent silver oxide and monovalent silver oxide. The latter oxide is employed as an electrolyte-impermeable layer which is interposed between ~111494 the divalent silver oxide and the battery components containing the electrolyte so as to isolate the divalent silver oxide from contact with the electrolyte until the monovalent silver material is discharged. If the discharge product of the monovalent silver material is continually reoxidized by the divalent silver material in the presence of the battery electrolyte, then it is possible that the battery will yield a unipotential discharge.
In U. S. Patent 3,920,478 a silver oxide cell is disclosed which employs a positive electrode comprising divalent silver oxide housed in a positive cathode con-tainer, and interposed between the positive electrode and the inner wall of the cathode container and/or between the positive electrode and the separator is a discontinuous oxidizable metal, such as a zinc screen, which functions to reduce a portion of the divalent silver oxide to mono-valent silver oxide which isolates the divalent silver oxide portion of the positive electrode from the container . 20 90 as to produce a unipotential discharge on low drain conditions.
In U. S. Patent 3,925,102 a silver oxide cell is disclosed which employ~ a positive electrode comprising divalent silver oxide housed in a positive electrode container having an upstanding wall and a closed end.
Interposed between the positive electrode ant the inner upstanding wall is an oxidizable zinc ring which functions to reduce a portion of the divalent silver oxide to mono-valent silver oxide which isolates the divalent silver oxide portion of the positive electrode from the ccntainer so as to produce a unipotential discharge on low drain conditions.
The silver oxide electrodes for use in the above-described cells are generally molded into inflexible pellet-type solid electrodes with the aid of a lubricant. The presence of many of the conventional lubricants, such as graphite, in molded silver oxide electrodes containing divalent silver oxide has been found to adversely affect the shelf life of the cells employing such electrodes and/or the unipotential discharge characteristic of the cells.
Accordingly, it is an object of the present inven-tion to provide a metal oxide electrode for electrochemical cells which comprises a metal oxide and a minor amount of solid~ethylene acrylic acid poly~er.
Another ob;ect of this invention is to provide a silver oxide electrode for electrochemical cells which com-prises divalent silver oxide and a minor amount of an 2Q ethylene acrylic acid polymer.
Another object of this invention is to incorporate a minor amount of an ethylene acrylic acid polymer into a divalent silver oxide-containing material so as to provide lubricity and cohesion to the mixture so that said mixture can be easily molded into a substantially cohesive inflexible body which can be easily handled.
Another ob;ect of this invention is to provide a porous positive electrode for silver oxide cells which comprises divalent silver oxide and a minor amount of an ethylene acrylic acid polymer ancl which electrode will exhibit good electrolyte absorption characteristics.
Another object of this invention is to provide a method for producing a molded metal oxide electrode.
Summary of the Invention The invention relates to a molded metal oxide electrode, such as a silver oxide electrode, for use in electrochemical cells which comprises a metal oxide, such as divalent silver oxide, and a minor amount of an ethylene acrylic acid polymer, for example, between about 0.5 and about 10 weight per cent,preferably between about 1.0 and about
2 weightper cent, based on the weight of the dry powder constituents of the metal oxide electrode. The ethylene - acrylic acid polymer (EAA) for use in this invention is a solid copolymer of ethylene and acrylic acid, preferabl~ in powder form A method for producing a molded metal oxide electrode comprising the steps:
a) mixing a metal oxide powder with a minor amount of an ethylene acrylic acid polymer, for example, between about 0.5 and about 10 weight per cent based on the weight of the metal oxide powder; and b) compacting a metered portion of the mixture of step a) to form a pressed, molded metal oxide electrode.
Metal oxides for use in the process of this inven-tion comprise silver oxide (monovalent and divalent), mercury oxide, cadmium oxide man~anese dioxide, nickel oxide, nickel hydroxide, and mixtures thereof.
The ethylene acrylic acid additive for use in molding metal oxide electrodes, such as silver oxide elec-trodes, of this invention has been found to be a multi-purpose additive having the following advantages:
1) The primary advantage is that the ethylene acrylic acid copolymer additive functions as a lubricant and a flow agent in the pressure molding of metal oxide elec-trodes, such as electrode pellets.
2) The ethylene acrylic acid additive also functions as a binder in the metal oxite electrode and, therefore, imparts greater mechanical strength to a molted electrode.
a) mixing a metal oxide powder with a minor amount of an ethylene acrylic acid polymer, for example, between about 0.5 and about 10 weight per cent based on the weight of the metal oxide powder; and b) compacting a metered portion of the mixture of step a) to form a pressed, molded metal oxide electrode.
Metal oxides for use in the process of this inven-tion comprise silver oxide (monovalent and divalent), mercury oxide, cadmium oxide man~anese dioxide, nickel oxide, nickel hydroxide, and mixtures thereof.
The ethylene acrylic acid additive for use in molding metal oxide electrodes, such as silver oxide elec-trodes, of this invention has been found to be a multi-purpose additive having the following advantages:
1) The primary advantage is that the ethylene acrylic acid copolymer additive functions as a lubricant and a flow agent in the pressure molding of metal oxide elec-trodes, such as electrode pellets.
2) The ethylene acrylic acid additive also functions as a binder in the metal oxite electrode and, therefore, imparts greater mechanical strength to a molted electrode.
3) The ethylene acrylic acid is a hydrophilic material whic~ when mixed with a metal oxite and then suit-ably molted into a cohesive porous form, will produce a porous electrode having excellent electrolyte absorption characteristics with respect to both rate of absorption and volume of absorbate.
The addition of an ethylene acrylic acit polymer in a properly constructed divalent silver oxide/monovalent silver oxide-containing electrode. for use in an alkaline cell system will not interfere with cell operation and thus will enable the cell to exhibit a monovalent voltage output with greater reliability than an otherwise itentical cell with the exception that the electrote employs a different lubricant, such as graphite, rather than ethylene acrylic acit polymer.
As used herein, a silver oxide electrode shall - 11;114914 mean an electrode wherein the active cathode material is divalent silver oxide or an electrode wherein the major active material is divalent silver oxide in conjunction with an amount below 50% by weight of monovalent silver oxide and/or some other electrochemically active cathode material.
The minor amount of the ethylene acrylic acid addi-tive for use in the electrode of this invention should be between about 0.5 and about 10 per cent based on the weight of the dry powder constituents o the electrode and prefer-ably between about 1 and 2 weight per cent based on theweight of the dry powder constituents of the electrode. An amount of ethylene acrylic acid polymer less than, for example, about 0.5 weight per cent, would not provide suffi-cient lubricity to the electrode mix for reliable and effi-' cient molding and would not impart adequate cohesion to the molded electrode formed therefrom. An amount of ethylene acrylic acid polymer more than, for example, about 10 weight ' per cent added to the electrode mix would be detrimental to cell capacity since too much of the high capacity active cathode material would be physically replaced by the ethyleneacrylic acid polymer which is not an active reducible material. Consequently, the amount of the ethylene acrylic - acid polymer to be added should preferably be the minimum amount that will give good flow lubricity to the active cathode mix and cohesion to the electrode so formed.
--- --The pe~cent pacE-~'ir.g''of the compressed mix should be at-least above ~. - - - ~~ -It is also within the scope of this invention to . .
additionally add ~ min~r ~m~unt cf a stabilizer, a 9.
11114~4 flow agent and/or a lubricating agent to the activecathode mix, such as a silver oxide mix, to further alter the physical characteristics of the mix for molding purposes eo produce various size and type electrodes.
Examples of some of these additives are ethylene bis-stearamide, zinc stearate, lead stearate, calcium stearate, and the like.
Silver oxide electrodes of this invention may be employed in an aqueous cel~ system using an anode such as zinc, cadmium, indium, or the like. The electrode couple so selected can be employed with a compatible electrolyte and preferably an alkaline electro~yte~ Examples of suitable electrolytes include alkaline earth metal hydroxides, such as strontium hydroxide and alkali metal hydroxides, exemplified by sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide and cesium hydroxide. Compatible mixtures of the preceding may be utilized. Preferably, the molded electrode of this invention should be porous so that the walls of the pores and interstices of the electrode can become wetted by the electrolyte.
The silver oxite electrode of this invention can also be employed in non-aqueous cell systems employing an anode such as lithium, sodium, potassium, calcium, magnesium, or their alloys. Again, the electrode couple qo selected should be employed with a compatible non-aqueous electrolyte which preferably will not dissolve 10.
or otherwise attack the ethylene acrylic acid additive.
EXAMPLE I
To demonstrate the increased pellet strength and the excellent electrolyte absorption characteristics of the pellet made in accordance with this invention, pellets were molded from each of the silver oxide-containing mixes shown in Table 1. The pellets measured 0.435 inch (1.1 cm) in diameter by 0.051 inch (0.13 cm), weighed about 0.64 gm and had a density as shown in Table 1.
A 33 per cent by weight potassium hydroxide electro-lyte was fed on top of each pellet and after six minutes the amount of electrolyte absorbed into the pellets was observed.
The average electrolyte absorption and pellet break strength measurements for five cathode pellets were calculated and are shown in Table 1. These data clearly de nstrate that the ethylene acrylic acid-containing pellets had superior electrolyte absorption characteristics and strength over 100% divalent silver oxide pellets and divalent silver oxide pellets containing a minor amount of lead stearate.
Avg. Absorbed Pellet Cathode Mix Densit~ Electrolyte Strength (Dry) Com~osition (gm/in~) (milligrams) (kilograms) . _ .
100% AgO 85 47 9.8 99.5% AgO, 0.5% 85 42 9.8 lead stearate*
99% AgO, 1% EAA** 86 52 13.2 *Lead stearate was added as a lubricant to facilitate lding of the pellets.
**The particular EAA material used was a solid powder and had an acrylic acid content of 20%, a DTA-melting point of 95C
and a melt index of 50 gm/10 min. at 190C.
(1) The average break strength as determined by Stokes hardness tester (F.J. Stokes Machine Co., Phila., Pa.
11 .
EXAMPLE II
To further demonstrate the excellent electrolyte absorption characteristics of the silver oxide electrodes of this invention, seven pellets were molded from each of the silver oxide-containing mixes shown in Table 2.
The pellets measured 0.434 inch (1.1 cm) in diameter, 0.023 inch (0.058 cm) high, and weighed about 0.30 gram.
Eighteen milligrams of a 33 per cent potassium hydroxide electrolyte were fed on top of each pellet and the time required for the electrolyte to be completely absorbed into the pellet was observed. The time range observed for four pellets made from each of the cathode mixes along with the average pellet strength of the remaining three pellets as obtained from using a Stokes Hardness tester are shown in Table 2. These data clearly demonstrate that the ethylene acrylic acid polymer-containing AgO/Ag2O pellets had superior electrolyte absorption charac-teristics ant pellet strength over AgO/Ag2O pellets contain-ing a minor amount of the lubriGant, lead stearate.
Absorption**
Avg. Time for Pellet***
Cathode MixDensity 18 milligrams Strength Composition (gm/in3) (minutes)(kilograms) and 1% ~ 92 3-6 8.4 80% AgO, 19-3/4% 93 9-16 6.9 Ag2O and 1/4% lead stearate*
30*Lead stearate was added as a lubricant to facilitate molding of the pellets.
**Measured range for four pellets.
***Average reading of three pellets.
EXAMPLE III
Several lots of cells, each cell sized 0.455 inch (1.16 cm) in diameter by 0.105 inch (0.267 cm) high, were made us~ng a molded cathode of 80 per cent divalent silver oxide, 16.1 to 19.75 per cent novalent siLver oxide ant the remainder a lubricant, specifically lead stearate, EAA polymer, or graphite; a zinc anode and a 33 per cent potassium hydroxide electrolyte. A separator, composet of a fibrous sheet and a laminate consisting of a layer of cross-linked polyethylene and a layer of cello-phane having a gold metallized coating on the polyethylene side, was disposed between the zinc anode and the silver oxide electrode. The gold metallized side of the laminate (polyethylene side) was in contact with the silver oxide electrode. To insure a monovalent silver oxide voltage output, a zinc screen was placed between the cathode and the nickel-plated cathode container as taught in U. S.
Patent 3,920,478. To complete the cell assembly, a gold-plated, copper clad, 3tainless steei anode cup containing the anote and nylon gasket was radially sealed by the con-ventional swaging and crimping technique.
Each lot of these cells was tested in several ways and the data so obtained are shown in Tables 3 to 9.
Tables 3 and 4 show the anode and cathode com-positions used in the test cells. Table 5 shows open circuit voltages as a function of time at 21C. Table 6 shows the number of test cells whose open circuit voltages were below 1.80 volts after specified storage periods at 21C. Table 7 11114~4 shows closed circuit voltages on 62,000-ohm continuous discharge. The numbers shown are the average voltages for each lot of cells under the conditions indicated in the table. Table 8 shows the average closed circuit vol-tages at the end of a two-second discharge on 30 and 100 ohms after the storage periods (at 21C) indicated in the table. Table 9 shows the results of cell bottom bulging measurements, The values shown are the average and maximum bulge measurements after storage under the conditions indi-cated expressed as 0.001-inch increments (i.e., 2.6 - 0.0026-inch bulge).
.
ANODE CO~OS ITIONS
A~re .
Test % % % % 7 Angdte No. Zinc H~ CMC 4570 KOHH2~ (~2m) 65.0 3.93.18 20.47 7.45 .147 2 65.0 3.93.18 20.47 7.45 .147 3 66.5 4.0 3.2 19.5 6.8 .144
The addition of an ethylene acrylic acit polymer in a properly constructed divalent silver oxide/monovalent silver oxide-containing electrode. for use in an alkaline cell system will not interfere with cell operation and thus will enable the cell to exhibit a monovalent voltage output with greater reliability than an otherwise itentical cell with the exception that the electrote employs a different lubricant, such as graphite, rather than ethylene acrylic acit polymer.
As used herein, a silver oxide electrode shall - 11;114914 mean an electrode wherein the active cathode material is divalent silver oxide or an electrode wherein the major active material is divalent silver oxide in conjunction with an amount below 50% by weight of monovalent silver oxide and/or some other electrochemically active cathode material.
The minor amount of the ethylene acrylic acid addi-tive for use in the electrode of this invention should be between about 0.5 and about 10 per cent based on the weight of the dry powder constituents o the electrode and prefer-ably between about 1 and 2 weight per cent based on theweight of the dry powder constituents of the electrode. An amount of ethylene acrylic acid polymer less than, for example, about 0.5 weight per cent, would not provide suffi-cient lubricity to the electrode mix for reliable and effi-' cient molding and would not impart adequate cohesion to the molded electrode formed therefrom. An amount of ethylene acrylic acid polymer more than, for example, about 10 weight ' per cent added to the electrode mix would be detrimental to cell capacity since too much of the high capacity active cathode material would be physically replaced by the ethyleneacrylic acid polymer which is not an active reducible material. Consequently, the amount of the ethylene acrylic - acid polymer to be added should preferably be the minimum amount that will give good flow lubricity to the active cathode mix and cohesion to the electrode so formed.
--- --The pe~cent pacE-~'ir.g''of the compressed mix should be at-least above ~. - - - ~~ -It is also within the scope of this invention to . .
additionally add ~ min~r ~m~unt cf a stabilizer, a 9.
11114~4 flow agent and/or a lubricating agent to the activecathode mix, such as a silver oxide mix, to further alter the physical characteristics of the mix for molding purposes eo produce various size and type electrodes.
Examples of some of these additives are ethylene bis-stearamide, zinc stearate, lead stearate, calcium stearate, and the like.
Silver oxide electrodes of this invention may be employed in an aqueous cel~ system using an anode such as zinc, cadmium, indium, or the like. The electrode couple so selected can be employed with a compatible electrolyte and preferably an alkaline electro~yte~ Examples of suitable electrolytes include alkaline earth metal hydroxides, such as strontium hydroxide and alkali metal hydroxides, exemplified by sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide and cesium hydroxide. Compatible mixtures of the preceding may be utilized. Preferably, the molded electrode of this invention should be porous so that the walls of the pores and interstices of the electrode can become wetted by the electrolyte.
The silver oxite electrode of this invention can also be employed in non-aqueous cell systems employing an anode such as lithium, sodium, potassium, calcium, magnesium, or their alloys. Again, the electrode couple qo selected should be employed with a compatible non-aqueous electrolyte which preferably will not dissolve 10.
or otherwise attack the ethylene acrylic acid additive.
EXAMPLE I
To demonstrate the increased pellet strength and the excellent electrolyte absorption characteristics of the pellet made in accordance with this invention, pellets were molded from each of the silver oxide-containing mixes shown in Table 1. The pellets measured 0.435 inch (1.1 cm) in diameter by 0.051 inch (0.13 cm), weighed about 0.64 gm and had a density as shown in Table 1.
A 33 per cent by weight potassium hydroxide electro-lyte was fed on top of each pellet and after six minutes the amount of electrolyte absorbed into the pellets was observed.
The average electrolyte absorption and pellet break strength measurements for five cathode pellets were calculated and are shown in Table 1. These data clearly de nstrate that the ethylene acrylic acid-containing pellets had superior electrolyte absorption characteristics and strength over 100% divalent silver oxide pellets and divalent silver oxide pellets containing a minor amount of lead stearate.
Avg. Absorbed Pellet Cathode Mix Densit~ Electrolyte Strength (Dry) Com~osition (gm/in~) (milligrams) (kilograms) . _ .
100% AgO 85 47 9.8 99.5% AgO, 0.5% 85 42 9.8 lead stearate*
99% AgO, 1% EAA** 86 52 13.2 *Lead stearate was added as a lubricant to facilitate lding of the pellets.
**The particular EAA material used was a solid powder and had an acrylic acid content of 20%, a DTA-melting point of 95C
and a melt index of 50 gm/10 min. at 190C.
(1) The average break strength as determined by Stokes hardness tester (F.J. Stokes Machine Co., Phila., Pa.
11 .
EXAMPLE II
To further demonstrate the excellent electrolyte absorption characteristics of the silver oxide electrodes of this invention, seven pellets were molded from each of the silver oxide-containing mixes shown in Table 2.
The pellets measured 0.434 inch (1.1 cm) in diameter, 0.023 inch (0.058 cm) high, and weighed about 0.30 gram.
Eighteen milligrams of a 33 per cent potassium hydroxide electrolyte were fed on top of each pellet and the time required for the electrolyte to be completely absorbed into the pellet was observed. The time range observed for four pellets made from each of the cathode mixes along with the average pellet strength of the remaining three pellets as obtained from using a Stokes Hardness tester are shown in Table 2. These data clearly demonstrate that the ethylene acrylic acid polymer-containing AgO/Ag2O pellets had superior electrolyte absorption charac-teristics ant pellet strength over AgO/Ag2O pellets contain-ing a minor amount of the lubriGant, lead stearate.
Absorption**
Avg. Time for Pellet***
Cathode MixDensity 18 milligrams Strength Composition (gm/in3) (minutes)(kilograms) and 1% ~ 92 3-6 8.4 80% AgO, 19-3/4% 93 9-16 6.9 Ag2O and 1/4% lead stearate*
30*Lead stearate was added as a lubricant to facilitate molding of the pellets.
**Measured range for four pellets.
***Average reading of three pellets.
EXAMPLE III
Several lots of cells, each cell sized 0.455 inch (1.16 cm) in diameter by 0.105 inch (0.267 cm) high, were made us~ng a molded cathode of 80 per cent divalent silver oxide, 16.1 to 19.75 per cent novalent siLver oxide ant the remainder a lubricant, specifically lead stearate, EAA polymer, or graphite; a zinc anode and a 33 per cent potassium hydroxide electrolyte. A separator, composet of a fibrous sheet and a laminate consisting of a layer of cross-linked polyethylene and a layer of cello-phane having a gold metallized coating on the polyethylene side, was disposed between the zinc anode and the silver oxide electrode. The gold metallized side of the laminate (polyethylene side) was in contact with the silver oxide electrode. To insure a monovalent silver oxide voltage output, a zinc screen was placed between the cathode and the nickel-plated cathode container as taught in U. S.
Patent 3,920,478. To complete the cell assembly, a gold-plated, copper clad, 3tainless steei anode cup containing the anote and nylon gasket was radially sealed by the con-ventional swaging and crimping technique.
Each lot of these cells was tested in several ways and the data so obtained are shown in Tables 3 to 9.
Tables 3 and 4 show the anode and cathode com-positions used in the test cells. Table 5 shows open circuit voltages as a function of time at 21C. Table 6 shows the number of test cells whose open circuit voltages were below 1.80 volts after specified storage periods at 21C. Table 7 11114~4 shows closed circuit voltages on 62,000-ohm continuous discharge. The numbers shown are the average voltages for each lot of cells under the conditions indicated in the table. Table 8 shows the average closed circuit vol-tages at the end of a two-second discharge on 30 and 100 ohms after the storage periods (at 21C) indicated in the table. Table 9 shows the results of cell bottom bulging measurements, The values shown are the average and maximum bulge measurements after storage under the conditions indi-cated expressed as 0.001-inch increments (i.e., 2.6 - 0.0026-inch bulge).
.
ANODE CO~OS ITIONS
A~re .
Test % % % % 7 Angdte No. Zinc H~ CMC 4570 KOHH2~ (~2m) 65.0 3.93.18 20.47 7.45 .147 2 65.0 3.93.18 20.47 7.45 .147 3 66.5 4.0 3.2 19.5 6.8 .144
4 66.5 4.0 3.2 19.5 6.8 .144 66.5 4.0 3.2 19.5 6.8 .145 6 66.5 4.0 3.2 19.5 6.8 .145 CATHODE CO~POS ITIONS
A~Te .
TLe tt % % % lead % Cat~ .
~lo. A~O Ag~O EM Stearate Grap~ite (gm) .
19 3/4 0 1/4 0 .334 2 80 19 1 0 0 .309 3 80 19 3/4 0 1/4 0 .323 4 80 19 1 0 0 .308 19 1 0 0 .301 6 77.7 18.4 1 0 2.9 .313 MONOVALEN$ ~OLTAGE
CONTROL
es~ lA~ erage Ol :V (volts) . Lot Lubricant Added One One Three Six N2De No. to Cathode Week MonthMonths Months Months 1% EAA 1.599 1.602 1.738 1.636 6 l~o E~ and 1. 847 1.856 1.848 1.848 2. 9~0 Graphite 1 lt4qo lead 1. 778 1.849 1.849 1.840 1.826 stearate 2 1% EAA 1.606 1.648 1.744 1.698 1.708 3 1 /4~o lead1. 788 1.779 1.849 1.847 _ _ stearate 4 1% E~LA 1.594 1.649 1.761 1.795 __ Notes:
OCV - open circuit voltage 1. 5 cells per lot tested 16.
oo~
o .Y P ~ ~ o `I 1~ ~ ~ ~ ~
O~ D ~ 2 D
I C O ~ C
~ ;` ~ tL-~
;~ ~ ;~ D
~Z~ ~
,, ~ o ~ n _ ~, ~ ~ t~ o ~ r~
t~ In ~ m n ~
_~ _ _ _ _ _ _ ._ o c In o _ In ~ ,n o~
d ~ r- a~ c~ r~
. ~ ~ ~ . . . .
_ _ _ _ _ _ _ ~ ~ o In o _-- ~ ~ In Z 1, ~ ~ ~ o ~n C: ~ ~ O 'n cc~ ~ 'n n _ _ _ _ _ _ .
In o o In ~ ~ ~ - In ~ - ~ o ~ ~ ~ r~
o ~o ~ ~3 u~ oo r~ n ~ ~ ~ l - - - - - -c ~o o o o-~ o o ~ l~--~ ~
~ ¢ 3 u ~ ~ ~
o~ , ~ U
~ o o o o o - ~ ~ .. o _ ~ ~ o ~ o r~ ., ~
O ~ ~ o ~ ~
~1 I _ ~ 4 ~ ~
~ ~ ~ o .C "~ ~ O CJ
C~
e~ ~ ~ O C~
~:1 P ~1 ~1 ..
JJ ' JJ ~
<~ ~ 0 ~ O
C ~ C ~ ~ Z
~ P~
~ O ~
Z ~ ~O
18 .
C CO ~,, . .
~ o . . . . -~ _ _ _,,,,, a ~ ~ . .
.
_ C: U~
~ g ~ O
~ _ _ _ _ _ C O
~ O
_ ~ O
o ~ ~r ~ ~ ~ ~o a o ,. _ _ _ _ _ ~¦ a ¢O _ 3 ~1 , c ~
~,1 ~ ~ ~ ~ .
~ OC ~ ~ ~ ~ ~
_ ~ , ~.~
e ~ Oc ~ . ~ :
O ~ _ ~1 ~ ~ `O ~1 O ~ ~ ~
~ ~5 O _ _ _ _ _ _ ::
~1 ~ ~ ~.
O
_ ~ ~
lu z ~ D
_ , ..... . _ .... _ _ . . _ 19 .
_r g .
X _~
~ I I I o o U~ U~ o ~;~; u~
t ¢ I I I I
_ ~U ~ ~ _l ~1 0 0 C~
0~ P o o o o o _i JJ ~ ~
, ~C ~ ~ ¢ ' ' ' ' 0~~ 0 .,_ 0~ ~, ~ ~ ~ o ~ _l ,.;
o P O
¢ o o ~ o .~e .~
. ~ ~,C`l CO
~ i ~ o _I r i~ p:~ ~ ¢ O O O O ~ 0 ~0 S~
~1 ~c ~ ~ ~a) P O
. . ~ (iD _ ~ .~; 2 ,',' ' bO ~ ~ ,Q 0~ 0 0 c~
o ~ ~ 0 ~ ~ . .~
* ~ Il~ ¢ ~1 0 0 ~ ~ ~ O
J- S~ ~ ~ ~ 00 _ J-C O ~ 0 ~0 s e ~ ~ ~
0 ~ ~ ~ ~ ~ 0 ~ ¢ ¢ ¢ ~ o o~ o c, ~ a~ J
~ ~ ~~ ~,~ C~
0 c~ -- ~ ~ ~ a~~ ~ ~ ?
~ ~ C~ U
~ O
_læ
U~
-20 .
The meaning of the above data shown in Tables
A~Te .
TLe tt % % % lead % Cat~ .
~lo. A~O Ag~O EM Stearate Grap~ite (gm) .
19 3/4 0 1/4 0 .334 2 80 19 1 0 0 .309 3 80 19 3/4 0 1/4 0 .323 4 80 19 1 0 0 .308 19 1 0 0 .301 6 77.7 18.4 1 0 2.9 .313 MONOVALEN$ ~OLTAGE
CONTROL
es~ lA~ erage Ol :V (volts) . Lot Lubricant Added One One Three Six N2De No. to Cathode Week MonthMonths Months Months 1% EAA 1.599 1.602 1.738 1.636 6 l~o E~ and 1. 847 1.856 1.848 1.848 2. 9~0 Graphite 1 lt4qo lead 1. 778 1.849 1.849 1.840 1.826 stearate 2 1% EAA 1.606 1.648 1.744 1.698 1.708 3 1 /4~o lead1. 788 1.779 1.849 1.847 _ _ stearate 4 1% E~LA 1.594 1.649 1.761 1.795 __ Notes:
OCV - open circuit voltage 1. 5 cells per lot tested 16.
oo~
o .Y P ~ ~ o `I 1~ ~ ~ ~ ~
O~ D ~ 2 D
I C O ~ C
~ ;` ~ tL-~
;~ ~ ;~ D
~Z~ ~
,, ~ o ~ n _ ~, ~ ~ t~ o ~ r~
t~ In ~ m n ~
_~ _ _ _ _ _ _ ._ o c In o _ In ~ ,n o~
d ~ r- a~ c~ r~
. ~ ~ ~ . . . .
_ _ _ _ _ _ _ ~ ~ o In o _-- ~ ~ In Z 1, ~ ~ ~ o ~n C: ~ ~ O 'n cc~ ~ 'n n _ _ _ _ _ _ .
In o o In ~ ~ ~ - In ~ - ~ o ~ ~ ~ r~
o ~o ~ ~3 u~ oo r~ n ~ ~ ~ l - - - - - -c ~o o o o-~ o o ~ l~--~ ~
~ ¢ 3 u ~ ~ ~
o~ , ~ U
~ o o o o o - ~ ~ .. o _ ~ ~ o ~ o r~ ., ~
O ~ ~ o ~ ~
~1 I _ ~ 4 ~ ~
~ ~ ~ o .C "~ ~ O CJ
C~
e~ ~ ~ O C~
~:1 P ~1 ~1 ..
JJ ' JJ ~
<~ ~ 0 ~ O
C ~ C ~ ~ Z
~ P~
~ O ~
Z ~ ~O
18 .
C CO ~,, . .
~ o . . . . -~ _ _ _,,,,, a ~ ~ . .
.
_ C: U~
~ g ~ O
~ _ _ _ _ _ C O
~ O
_ ~ O
o ~ ~r ~ ~ ~ ~o a o ,. _ _ _ _ _ ~¦ a ¢O _ 3 ~1 , c ~
~,1 ~ ~ ~ ~ .
~ OC ~ ~ ~ ~ ~
_ ~ , ~.~
e ~ Oc ~ . ~ :
O ~ _ ~1 ~ ~ `O ~1 O ~ ~ ~
~ ~5 O _ _ _ _ _ _ ::
~1 ~ ~ ~.
O
_ ~ ~
lu z ~ D
_ , ..... . _ .... _ _ . . _ 19 .
_r g .
X _~
~ I I I o o U~ U~ o ~;~; u~
t ¢ I I I I
_ ~U ~ ~ _l ~1 0 0 C~
0~ P o o o o o _i JJ ~ ~
, ~C ~ ~ ¢ ' ' ' ' 0~~ 0 .,_ 0~ ~, ~ ~ ~ o ~ _l ,.;
o P O
¢ o o ~ o .~e .~
. ~ ~,C`l CO
~ i ~ o _I r i~ p:~ ~ ¢ O O O O ~ 0 ~0 S~
~1 ~c ~ ~ ~a) P O
. . ~ (iD _ ~ .~; 2 ,',' ' bO ~ ~ ,Q 0~ 0 0 c~
o ~ ~ 0 ~ ~ . .~
* ~ Il~ ¢ ~1 0 0 ~ ~ ~ O
J- S~ ~ ~ ~ 00 _ J-C O ~ 0 ~0 s e ~ ~ ~
0 ~ ~ ~ ~ ~ 0 ~ ¢ ¢ ¢ ~ o o~ o c, ~ a~ J
~ ~ ~~ ~,~ C~
0 c~ -- ~ ~ ~ a~~ ~ ~ ?
~ ~ C~ U
~ O
_læ
U~
-20 .
The meaning of the above data shown in Tables
5 through 9 can be summarized as follows:
1. As shown in Tables 5 and 6, the monovalent voltage of 1.56 to 1.60 volts is more reli-ably achieved when EAA polymer is used only as the cathode molding lubricant. This was determined by the monthly OCV measurements.
2. As shown in Table 7, cells containing graphite in the active cathode did not exhibit novalent voltage control on the 62,000-ohm continuous discharge te~t, thus de nstrating that they are not com-mercially usable in applications requiring the standard 1.60 volts. All cells in which EAA polymer was used as the only cathode molding lubricant exhibited the desired novalent voltage on the 62,000-ohm test.
3. As shown in Table 8, cells containing graphite in the active cathode exhibit the best performance on the two-second long 30- or 100-ohm pulse test; however, these cells did not exhibit the desired monovalent voltage, again de nstrating their lack of commercial utility in this type of application.
4. Cells containing EAA polymer as the lubricant in the active cathode exhibit higher closed circuit volt2ges on the high drain 30-ohm pulse, when compared with - cells using lead stearate as the lubricant.
Although the closed circuit voltages obtained in this test were higher with graphite than with EAA polymer, cells containing only the latter consistently displayed the desired novalent voltage.
5. The data shown in Table 9 clearly demonstrate that the cells using silver oxide electrodes fabricated with the EAA polymer lubricant exhibited a low bulge under the indicated storage conditions at various temperatures.
Since bulging was in the same range in all cases, these data indicate that EAA polymer does not have a detrimental effect on the stability of the cells after storage.
In actual practice, it is not feasible to make certain metal oxide cathode pellets, such as silver oxide cathode pellets, without a lubricant due to the tableting press "freezing up" after only a short period of operation.
Further, it has been found that the use of EAA as the lubricant for the metal oxide cathode mix will not adversely affect the functioning of the cathode in a cell system, such as a silver oxide electrode in a zinc KOH system.
It is to be understood that other modifications and changes to the preferred embodiments of the invention herein shown and described can also be made without departing from the spirit and scope of the invention.
.
':
1. As shown in Tables 5 and 6, the monovalent voltage of 1.56 to 1.60 volts is more reli-ably achieved when EAA polymer is used only as the cathode molding lubricant. This was determined by the monthly OCV measurements.
2. As shown in Table 7, cells containing graphite in the active cathode did not exhibit novalent voltage control on the 62,000-ohm continuous discharge te~t, thus de nstrating that they are not com-mercially usable in applications requiring the standard 1.60 volts. All cells in which EAA polymer was used as the only cathode molding lubricant exhibited the desired novalent voltage on the 62,000-ohm test.
3. As shown in Table 8, cells containing graphite in the active cathode exhibit the best performance on the two-second long 30- or 100-ohm pulse test; however, these cells did not exhibit the desired monovalent voltage, again de nstrating their lack of commercial utility in this type of application.
4. Cells containing EAA polymer as the lubricant in the active cathode exhibit higher closed circuit volt2ges on the high drain 30-ohm pulse, when compared with - cells using lead stearate as the lubricant.
Although the closed circuit voltages obtained in this test were higher with graphite than with EAA polymer, cells containing only the latter consistently displayed the desired novalent voltage.
5. The data shown in Table 9 clearly demonstrate that the cells using silver oxide electrodes fabricated with the EAA polymer lubricant exhibited a low bulge under the indicated storage conditions at various temperatures.
Since bulging was in the same range in all cases, these data indicate that EAA polymer does not have a detrimental effect on the stability of the cells after storage.
In actual practice, it is not feasible to make certain metal oxide cathode pellets, such as silver oxide cathode pellets, without a lubricant due to the tableting press "freezing up" after only a short period of operation.
Further, it has been found that the use of EAA as the lubricant for the metal oxide cathode mix will not adversely affect the functioning of the cathode in a cell system, such as a silver oxide electrode in a zinc KOH system.
It is to be understood that other modifications and changes to the preferred embodiments of the invention herein shown and described can also be made without departing from the spirit and scope of the invention.
.
':
Claims (19)
1. A molded metal oxide electrode for use in electrochemical cells which comprises a metal oxide and a minor amount of an ethylene acrylic acid polymer.
2. The molded metal oxide electrode of claim 1 wherein the metal oxide is selected from at least one of the oxides consisting of silver oxide (monovalent and divalent), mercury oxide, cadmium oxide, manganese dioxide, nickel oxide, and nickel hydroxide.
3. The metal oxide electrode of claim 1 wherein said ethylene acrylic acid polymer is present in an amount of between about 0.5 and about 10 weight per cent based on the weight of the dry powder constituents of the metal oxide electrode.
4. The metal oxide electrode of claim 3 wherein said ethylene acrylic acid polymer is present in an amount of between about 1 and about 2 per cent based on the weight of the dry powder constituents of the metal oxide electrode.
5. The metal oxide electrode of claim 2 wherein said ethylene acrylic acid polymer is present in an amount of between about 0.5 and about 10 weight per cent based on the weight of the dry powder constituents of the metal oxide electrode.
6. The metal oxide electrode of claim 5 wherein said ethylene acrylic acid polymer is present in an amount of between about 1 and about 2 per cent based on the weight of the dry powder constituents of the metal oxide electrode.
23.
23.
7. The metal oxide electrode of claim 1 wherein the metal oxide comprises divalent silver oxide.
8. The silver oxide electrode of claim 7 wherein said ethylene acrylic acid polymer is present in an amount of between about 0.5 and about 10 weight per cent based on the weight of the dry powder constituents of the silver oxide electrode.
9. The silver oxide electrode of claim 7 wherein said electrode contains less than 50 per cent by weight of monovalent silver oxide based on the weight of the dry pow-der constituents of the silver oxide electrode.
10. The silver oxide electrode of claim 9 wherein said ethylene acrylic acid polymer is present in an amount of between about 0.5 and about 10 weight per cent based on the weight of the dry powder constituents of the silver oxide electrode.
11. The silver oxide electrode of claim 7 wherein said 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 electrode of claim 11 wherein said ethylene acrylic acid polymer is present in an amount of between about 0.5 and about 10 weight per cent based on the weight of the dry powder constituents of the silver oxide electrode.
13. An alkaline cell employing a zinc anode, a metal oxide electrode comprising divalent silver oxide and a minor amount of ethylene acrylic acid polymer, and a potassium hydroxide electrolyte.
24.
24.
14. The alkaline cell of claim 13 wherein the silver oxide electrode contains less than 50 per cent by weight of monovalent silver oxide based on the weight of the dry powder constituents of the silver oxide electrode.
15. A method for producing a molded metal oxide electrode comprising the steps:
a) mixing a metal oxide powder with a minor amount of an ethylene acrylic acid polymer; and b) compacting a metered portion of the mixture of step a) to form a pressed, molded metal oxide electrode.
a) mixing a metal oxide powder with a minor amount of an ethylene acrylic acid polymer; and b) compacting a metered portion of the mixture of step a) to form a pressed, molded metal oxide electrode.
16. The method of claim 15 wherein said ethylene acrylic acid polymer is present in an amount of between about 0.5 and about 10 weight per cent based on the weight of the metal oxide powder.
17. The method of claim 16 wherein said metal oxide is selected from at least one of the oxides consisting of silver oxide (monovalent and divalent), mercury oxide, cadmium oxide, manganese dioxide, nickel oxide, and nickel hydroxide.
18. The method of claim 17 wherein said metal oxide is divalent silver oxide.
19. The method of claim 17 wherein said metal oxide is divalent silver oxide and monovalent silver oxide.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US890,972 | 1978-03-28 | ||
| US05/890,972 US4146685A (en) | 1978-03-28 | 1978-03-28 | Molded metal oxide electrodes containing an ethylene acrylic acid additive |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1111494A true CA1111494A (en) | 1981-10-27 |
Family
ID=25397404
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA322,242A Expired CA1111494A (en) | 1978-03-28 | 1979-02-22 | Molded metal oxide electrodes containing an ethylene acrylic acid additive |
Country Status (16)
| Country | Link |
|---|---|
| US (1) | US4146685A (en) |
| JP (1) | JPS54164224A (en) |
| AT (1) | AT369928B (en) |
| AU (1) | AU528526B2 (en) |
| BE (1) | BE875128A (en) |
| CA (1) | CA1111494A (en) |
| CH (1) | CH629625A5 (en) |
| DE (1) | DE2911013C2 (en) |
| DK (1) | DK124679A (en) |
| FR (1) | FR2421469A1 (en) |
| GB (1) | GB2020477B (en) |
| HK (1) | HK88286A (en) |
| IT (1) | IT1113048B (en) |
| MX (1) | MX151479A (en) |
| NL (1) | NL7902382A (en) |
| SE (1) | SE445277B (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4167609A (en) * | 1978-03-30 | 1979-09-11 | Union Carbide Corporation | Zinc oxide additive for divalent silver oxide electrodes |
| CA1128121A (en) * | 1978-03-30 | 1982-07-20 | Union Carbide Corporation | Cadium compound additive for cells using divalent silver oxide |
| FR2440086A1 (en) * | 1978-10-27 | 1980-05-23 | Comp Generale Electricite | ELECTRODE FOR LEAD ACCUMULATOR |
| US4228228A (en) * | 1979-10-04 | 1980-10-14 | Bell Telephone Laboratories, Incorporated | Electrode structure for energy cells |
| US4391729A (en) * | 1979-12-17 | 1983-07-05 | Wilson Greatbatch Ltd. | Metal oxide composite cathode material for high energy density batteries |
| DE69226513T2 (en) * | 1991-10-09 | 1998-12-10 | Yuasa Battery Co Ltd | USE OF A MACROMOLECULAR COMPOUND FOR PRODUCING A DEPOLARIZING MIXTURE |
| US5981105A (en) * | 1996-07-08 | 1999-11-09 | Emf Systems, Inc. | High rate metal oxide electrodes |
| US6165641A (en) * | 1997-05-09 | 2000-12-26 | The United States Of America As Represented By The United States Department Of Energy | Nanodisperse transition metal electrodes (NTME) for electrochemical cells |
| EP1341248A1 (en) * | 2000-11-17 | 2003-09-03 | Toshiba Battery Co., Ltd. | Enclosed nickel-zinc primary battery, its anode and production methods for them |
| NZ510554A (en) * | 2001-03-15 | 2003-08-29 | Univ Massey | Rechargeable zinc electrode comprising a zinc salt and a derivative of a fatty acid or alkyl sulfonic acid |
| US20030129410A1 (en) * | 2001-12-27 | 2003-07-10 | General Electric Company | Ultraviolet protective dual layer laminate for polycarbonate resin substrates and method of manufacture thereof |
| US7846575B2 (en) * | 2004-07-30 | 2010-12-07 | Medtronic, Inc. | Anode cup and methods of fabrication for medical grade electrochemical cells |
| WO2006085416A1 (en) * | 2005-02-10 | 2006-08-17 | Hitachi Chemical Company, Ltd. | Binder resin emulsion for energy device electrode, and energy device electrode and energy device using the same |
Family Cites Families (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1047395A (en) * | ||||
| US2811572A (en) * | 1955-04-01 | 1957-10-29 | Fischbach Adolph | Method for making silver peroxide electrodes |
| US2902530A (en) * | 1955-10-12 | 1959-09-01 | Bjorksten Res Lab Inc | Battery constituents |
| DE1790849U (en) * | 1958-09-24 | 1959-06-25 | Accumulatoren Fabrik Ag | POSITIVE ELECTRODE FOR GALVANIC PRIMARY ELEMENTS. |
| FR1314538A (en) * | 1961-11-30 | 1963-01-11 | Gadot Soc D Accumulateurs Ets | Process for preparing electrodes for primary or reversible elements, in particular silver elements |
| US3184339A (en) * | 1962-04-10 | 1965-05-18 | Grenville B Ellis | Battery electrode |
| US3120457A (en) * | 1962-11-23 | 1964-02-04 | Electric Storage Battery Co | Method of manufacturing fuel cell and/or battery electrode |
| DE1771522A1 (en) * | 1968-06-04 | 1972-03-09 | Varta Ag | Silver oxide electrode for alkaline primary elements and process for their production |
| US3706601A (en) * | 1970-01-28 | 1972-12-19 | Mc Donnell Douglas Corp | Method of producing an electrode with a polymer binder by rolling |
| US3918989A (en) * | 1971-01-18 | 1975-11-11 | Gates Rubber Co | Flexible electrode plate |
| US3954506A (en) * | 1971-11-16 | 1976-05-04 | Polaroid Corporation | Zinc anode and composition and method for producing same |
| JPS5234734B2 (en) * | 1972-10-28 | 1977-09-05 | ||
| US3898099A (en) * | 1974-03-18 | 1975-08-05 | Energy Res Corp | Hydrophilic electrode and method for making the same |
| JPS52125724A (en) * | 1976-04-13 | 1977-10-21 | Hitachi Maxell | Alkaline battery |
| JPS5931185B2 (en) * | 1976-04-13 | 1984-07-31 | 日立マクセル株式会社 | alkaline secondary battery |
| US4056664A (en) * | 1977-01-28 | 1977-11-01 | P. R. Mallory & Co. Inc. | Electrochemical cell having an AgO electrode discharging at an Ag2 O voltage level |
-
1978
- 1978-03-28 US US05/890,972 patent/US4146685A/en not_active Expired - Lifetime
-
1979
- 1979-02-22 CA CA322,242A patent/CA1111494A/en not_active Expired
- 1979-03-21 DE DE2911013A patent/DE2911013C2/en not_active Expired
- 1979-03-27 GB GB7910714A patent/GB2020477B/en not_active Expired
- 1979-03-27 MX MX177079A patent/MX151479A/en unknown
- 1979-03-27 FR FR7907682A patent/FR2421469A1/en active Granted
- 1979-03-27 BE BE0/194244A patent/BE875128A/en not_active IP Right Cessation
- 1979-03-27 AT AT0227679A patent/AT369928B/en not_active IP Right Cessation
- 1979-03-27 CH CH283679A patent/CH629625A5/en not_active IP Right Cessation
- 1979-03-27 IT IT21349/79A patent/IT1113048B/en active
- 1979-03-27 NL NL7902382A patent/NL7902382A/en not_active Application Discontinuation
- 1979-03-27 JP JP3618179A patent/JPS54164224A/en active Granted
- 1979-03-27 DK DK124679A patent/DK124679A/en not_active IP Right Cessation
- 1979-03-27 SE SE7902720A patent/SE445277B/en not_active IP Right Cessation
- 1979-03-27 AU AU45427/79A patent/AU528526B2/en not_active Ceased
-
1986
- 1986-11-20 HK HK882/86A patent/HK88286A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| FR2421469B1 (en) | 1984-10-12 |
| BE875128A (en) | 1979-09-27 |
| GB2020477B (en) | 1982-08-04 |
| SE7902720L (en) | 1979-09-29 |
| US4146685A (en) | 1979-03-27 |
| AU4542779A (en) | 1979-10-04 |
| NL7902382A (en) | 1979-10-02 |
| CH629625A5 (en) | 1982-04-30 |
| JPS6241381B2 (en) | 1987-09-02 |
| AU528526B2 (en) | 1983-05-05 |
| DE2911013A1 (en) | 1979-10-11 |
| IT1113048B (en) | 1986-01-20 |
| MX151479A (en) | 1984-12-03 |
| HK88286A (en) | 1986-11-28 |
| GB2020477A (en) | 1979-11-14 |
| IT7921349A0 (en) | 1979-03-27 |
| ATA227679A (en) | 1982-06-15 |
| FR2421469A1 (en) | 1979-10-26 |
| AT369928B (en) | 1983-02-10 |
| JPS54164224A (en) | 1979-12-27 |
| SE445277B (en) | 1986-06-09 |
| DK124679A (en) | 1979-09-29 |
| DE2911013C2 (en) | 1982-06-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5340666A (en) | Rechargeable alkaline manganese cell having improved capacity and improved energy density | |
| EP0694215B1 (en) | Electrochemical cell with zinc anode | |
| CN100514714C (en) | Alkaline battery including nickel oxyhydroxide cathode and zinc anode | |
| US7169508B2 (en) | Method of manufacturing anode compositions for use in rechargeable electrochemical cells | |
| US5300371A (en) | Manganese dioxide positive electrode for rechargeable cells, and cells containing the same | |
| US3956018A (en) | Primary electric current-producing dry cell using a (CFx)n cathode and an aqueous alkaline electrolyte | |
| US4085259A (en) | Light metal galvanic element | |
| CA1111494A (en) | Molded metal oxide electrodes containing an ethylene acrylic acid additive | |
| AU2006317436B2 (en) | Rechargeable alkaline manganese cell having reduced capacity fade and improved cycle life | |
| US4048405A (en) | High drain rate, primary alkaline cell having a divalent silver oxide/monovalent silver oxide depolarizer blend coated with a layer of silver | |
| GB2028565A (en) | Alkaline primary cells | |
| US4158723A (en) | High specific energy battery | |
| US4167609A (en) | Zinc oxide additive for divalent silver oxide electrodes | |
| JP2003502808A (en) | Alkaline battery with improved anode | |
| CA1077131A (en) | Metal oxide cells having low internal impedance | |
| US5164274A (en) | Zinc anodes for alkaline galvanic cells, and cells containing them | |
| KR19990044021A (en) | Additives for alkaline electrochemical cells with manganese dioxide anode | |
| US4056664A (en) | Electrochemical cell having an AgO electrode discharging at an Ag2 O voltage level | |
| EP0077614A2 (en) | Alkaline electrochemical cells | |
| US20040013933A1 (en) | Fluorinated carbon for metal/fluorinated carbon batteries | |
| US20060003225A1 (en) | Alkaline dry battery | |
| KR100802860B1 (en) | Alkaline dry battery | |
| CA1123898A (en) | Lithium-lead sulfate primary electrochemical cell | |
| JP2003151539A (en) | Alkaline dry cell | |
| US4250234A (en) | Divalent silver oxide cell |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |