GB2119160A - Divalent silver oxide cell - Google Patents
Divalent silver oxide cell Download PDFInfo
- Publication number
- GB2119160A GB2119160A GB8227135A GB8227135A GB2119160A GB 2119160 A GB2119160 A GB 2119160A GB 8227135 A GB8227135 A GB 8227135A GB 8227135 A GB8227135 A GB 8227135A GB 2119160 A GB2119160 A GB 2119160A
- Authority
- GB
- United Kingdom
- Prior art keywords
- silver oxide
- cell
- positive electrode
- divalent silver
- divalent
- 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.)
- Granted
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- NDVLTYZPCACLMA-UHFFFAOYSA-N silver oxide Substances [O-2].[Ag+].[Ag+] NDVLTYZPCACLMA-UHFFFAOYSA-N 0.000 title claims abstract description 321
- 229910001923 silver oxide Inorganic materials 0.000 title claims abstract description 205
- OTCVAHKKMMUFAY-UHFFFAOYSA-N oxosilver Chemical compound [Ag]=O OTCVAHKKMMUFAY-UHFFFAOYSA-N 0.000 title claims abstract description 89
- 229910052714 tellurium Inorganic materials 0.000 claims abstract description 18
- PORWMNRCUJJQNO-UHFFFAOYSA-N tellurium atom Chemical compound [Te] PORWMNRCUJJQNO-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910052793 cadmium Inorganic materials 0.000 claims abstract description 16
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 claims abstract description 16
- 229910052709 silver Inorganic materials 0.000 claims description 44
- 239000004332 silver Substances 0.000 claims description 44
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 43
- 239000011701 zinc Substances 0.000 claims description 16
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 14
- 239000011230 binding agent Substances 0.000 claims description 14
- 239000003792 electrolyte Substances 0.000 claims description 14
- 229910052751 metal Inorganic materials 0.000 claims description 14
- 239000000203 mixture Substances 0.000 claims description 14
- 229910052725 zinc Inorganic materials 0.000 claims description 13
- 238000011946 reduction process Methods 0.000 claims description 11
- 229910052782 aluminium Inorganic materials 0.000 claims description 6
- 239000004411 aluminium Substances 0.000 claims description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 6
- 229910052716 thallium Inorganic materials 0.000 claims description 6
- BKVIYDNLLOSFOA-UHFFFAOYSA-N thallium Chemical compound [Tl] BKVIYDNLLOSFOA-UHFFFAOYSA-N 0.000 claims description 6
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 5
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 claims description 5
- 229910052753 mercury Inorganic materials 0.000 claims description 5
- 229910052718 tin Inorganic materials 0.000 claims description 5
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 5
- 229910052721 tungsten Inorganic materials 0.000 claims description 5
- 239000010937 tungsten Substances 0.000 claims description 5
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 claims description 4
- 229910052732 germanium Inorganic materials 0.000 claims description 4
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 claims description 4
- 229910052746 lanthanum Inorganic materials 0.000 claims description 4
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 claims description 4
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 4
- 229910052711 selenium Inorganic materials 0.000 claims description 4
- 239000011669 selenium Substances 0.000 claims description 4
- 229910052727 yttrium Inorganic materials 0.000 claims description 4
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 claims description 4
- 239000000843 powder Substances 0.000 description 55
- 239000003381 stabilizer Substances 0.000 description 41
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 36
- CXKCTMHTOKXKQT-UHFFFAOYSA-N cadmium oxide Inorganic materials [Cd]=O CXKCTMHTOKXKQT-UHFFFAOYSA-N 0.000 description 29
- CFEAAQFZALKQPA-UHFFFAOYSA-N cadmium(2+);oxygen(2-) Chemical compound [O-2].[Cd+2] CFEAAQFZALKQPA-UHFFFAOYSA-N 0.000 description 29
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 28
- 229910052760 oxygen Inorganic materials 0.000 description 28
- 239000001301 oxygen Substances 0.000 description 28
- LAJZODKXOMJMPK-UHFFFAOYSA-N tellurium dioxide Chemical compound O=[Te]=O LAJZODKXOMJMPK-UHFFFAOYSA-N 0.000 description 28
- 239000008188 pellet Substances 0.000 description 22
- 238000003860 storage Methods 0.000 description 16
- WKMKTIVRRLOHAJ-UHFFFAOYSA-N oxygen(2-);thallium(1+) Chemical compound [O-2].[Tl+].[Tl+] WKMKTIVRRLOHAJ-UHFFFAOYSA-N 0.000 description 14
- 229910003438 thallium oxide Inorganic materials 0.000 description 14
- 239000000243 solution Substances 0.000 description 13
- 229910000108 silver(I,III) oxide Inorganic materials 0.000 description 12
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 9
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 239000002184 metal Substances 0.000 description 8
- YBMRDBCBODYGJE-UHFFFAOYSA-N germanium dioxide Chemical compound O=[Ge]=O YBMRDBCBODYGJE-UHFFFAOYSA-N 0.000 description 6
- 239000007774 positive electrode material Substances 0.000 description 5
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 4
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 4
- 239000005977 Ethylene Substances 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 239000002253 acid Substances 0.000 description 3
- 239000000654 additive Substances 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 238000010494 dissociation reaction Methods 0.000 description 3
- 230000005593 dissociations Effects 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 238000010292 electrical insulation Methods 0.000 description 3
- 229940119177 germanium dioxide Drugs 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000007773 negative electrode material Substances 0.000 description 3
- NLKNQRATVPKPDG-UHFFFAOYSA-M potassium iodide Chemical compound [K+].[I-] NLKNQRATVPKPDG-UHFFFAOYSA-M 0.000 description 3
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 2
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 2
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 229920002125 Sokalan® Polymers 0.000 description 2
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 239000012670 alkaline solution Substances 0.000 description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 description 2
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 2
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- HTUMBQDCCIXGCV-UHFFFAOYSA-N lead oxide Chemical compound [O-2].[Pb+2] HTUMBQDCCIXGCV-UHFFFAOYSA-N 0.000 description 2
- 239000004973 liquid crystal related substance Substances 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000004584 polyacrylic acid Substances 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 238000004445 quantitative analysis Methods 0.000 description 2
- 238000010079 rubber tapping Methods 0.000 description 2
- 235000002906 tartaric acid Nutrition 0.000 description 2
- 239000011975 tartaric acid Substances 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- ZUMMKALUNVXLCS-UHFFFAOYSA-N O=[Ag]=O Chemical compound O=[Ag]=O ZUMMKALUNVXLCS-UHFFFAOYSA-N 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 229910008649 Tl2O3 Inorganic materials 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 230000002745 absorbent Effects 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- PLLZRTNVEXYBNA-UHFFFAOYSA-L cadmium hydroxide Chemical compound [OH-].[OH-].[Cd+2] PLLZRTNVEXYBNA-UHFFFAOYSA-L 0.000 description 1
- WIKQEUJFZPCFNJ-UHFFFAOYSA-N carbonic acid;silver Chemical compound [Ag].[Ag].OC(O)=O WIKQEUJFZPCFNJ-UHFFFAOYSA-N 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012777 electrically insulating material Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 1
- 229910000765 intermetallic Inorganic materials 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910000474 mercury oxide Inorganic materials 0.000 description 1
- UKWHYYKOEPRTIC-UHFFFAOYSA-N mercury(ii) oxide Chemical compound [Hg]=O UKWHYYKOEPRTIC-UHFFFAOYSA-N 0.000 description 1
- 239000000615 nonconductor Substances 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- FXADMRZICBQPQY-UHFFFAOYSA-N orthotelluric acid Chemical compound O[Te](O)(O)(O)(O)O FXADMRZICBQPQY-UHFFFAOYSA-N 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- QTQRFJQXXUPYDI-UHFFFAOYSA-N oxo(oxothallanyloxy)thallane Chemical compound O=[Tl]O[Tl]=O QTQRFJQXXUPYDI-UHFFFAOYSA-N 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 229920006122 polyamide resin Polymers 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 150000003378 silver Chemical class 0.000 description 1
- LKZMBDSASOBTPN-UHFFFAOYSA-L silver carbonate Substances [Ag].[O-]C([O-])=O LKZMBDSASOBTPN-UHFFFAOYSA-L 0.000 description 1
- KQTXIZHBFFWWFW-UHFFFAOYSA-L silver(I) carbonate Inorganic materials [Ag]OC(=O)O[Ag] KQTXIZHBFFWWFW-UHFFFAOYSA-L 0.000 description 1
- VFWRGKJLLYDFBY-UHFFFAOYSA-N silver;hydrate Chemical compound O.[Ag].[Ag] VFWRGKJLLYDFBY-UHFFFAOYSA-N 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910021515 thallium hydroxide Inorganic materials 0.000 description 1
- QGYXCSSUHCHXHB-UHFFFAOYSA-M thallium(i) hydroxide Chemical compound [OH-].[Tl+] QGYXCSSUHCHXHB-UHFFFAOYSA-M 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 1
- 229920003169 water-soluble polymer Polymers 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
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
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/54—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of silver
-
- 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)
- Inorganic Chemistry (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Primary Cells (AREA)
Abstract
A divalent silver oxide cell has a positive electrode consisting of divalent silver oxide, cadmium and tellurium.
Description
SPECIFICATION
Divalent silver oxide cell
This invention relates to divalent silver oxide cells.
A conventional divalent silver oxide cell without a stabilizer added to the divalent silver oxide positive electrode lacks stability since the volume of oxygen produced as a result of dissociation or dissolution in the aqueous alkaline electrolyte is relatively large. Thus, the divalent silver oxide dissociation dissolves by itself in the aqueous alkaline electrolyte to reduce electrical capacity of the conventional divalent silver oxide cell.
Further, the oxygen evolved as a result of dissociation or dissolution of the divalent silver oxide oxidizes a separator which, as it deteriorates, causes self discharge of the conventional divalent silver oxide cell. The oxygen at the positive electrode diffuses and penetrates into a negative zinc electrode through the separator to oxidize the zinc thus further reducing electrical capacity. The accelerated oxidation of the negative zinc electrode causes the zinc surface to be coated with a passive coating of zinc oxide which stops the discharge of the conventional divalent silver oxide cell even if some active zinc remains. Thus a conventional divalent silver oxide cell using unstable divalent silver oxide as the positive electrode without the addition of a stabilizer has inferior storing characteristics.
The conventional divalent silver oxide cell also has the disadvantage of leakage of the alkaline electrolyte since the internal pressure increases as oxygen gradually accumulates.
In an attempt to eliminate the drawbacks of conventional divalent silver oxide cells it has been proposed to coat the surface of the divalent silver oxide powder with plumbate (plumbic acid silver). This is disclosed in
U.S. Patent Specification No. 3 017 448. Since the surface of the divalent silver oxide powder coated with silver plumbate is hard to reduce, it is difficult to form a silver layer on the surface of a positive electrode pellet formed from the powder and thus the battery impedance is increased.
The volume of oxygen evolved where 1000 ppm of zinc, cadmium, mercury, aluminium, indium, tellurium, tin, lead or tungsten are added to divalent silver oxide powder has been investigated by Aldar Tvarusko (J.
Electrochem. Soc:, 116, 1071(1969)). This paper shows that cadium, aluminium, lead, vanadium and chromium do not improve the stability of divalent silver oxide powder sufficiently.
According to the present invention there is provided a divalent silver oxide cell comprising a negative electrode, a positive electrode, said positive electrode consisting of divalent silver oxide, cadmium and tellurium.
Preferably said positive electrode includes one or more of lead, mercury, thallium, germanium, yttrium, tin, tungsten, lanthanum, rare earth element, zinc, selenium and aluminium.
Said positive electrode may have a silver layer on at least part of its outer surface.
Alternatively said positive electrode may be surrounded by a monovalent silver oxide layer which has a silver layer on at least part of its outer surface.
Said silver layer may be formed by reducing said divalent silver oxide.
Preferably the positive electrode includes an organic binder. In preferred embodiments the components of the positive electrode other than divalent silver oxide and organic binder are present in an amount between 10 to 5000 ppm.
Preferably the relationship between the thickness (A) of the silver layer and the amount (B) of the reduction
process is given by:
4.4 um/mAh < A/B < 8.1 Fam/mAh The invention is illustrated, merely by way of example, in the accompanying drawings, in which::
Figure 1 is a schematic sectional view of an experimental device to measure oxygen evolved in a divalent silver oxide cell;
Figure 2 illustrates graphically the oxygen evolved in divalent silver oxide cells where various additives
have been included in the divalent silver oxide positive electrode;
Figure 3 shows the relationship between the volume of oxygen evolved and the amount of cadmium and tellurium added to the divalent silver oxide positive electrode of a diva lent silver oxide cell according to the
present invention;
Figure 4 shows the relationship between storage time (days) of a divalent silver oxide cell according to the
present invention and a conventional divalent silver oxide cell;
Figure 5 is a section through a divalent silver oxide cell according to the present invention;;
Figure 6shows the relationship between the capacity degradation and the storage time at 600C and room temperature for conventional divalent silver oxide cells and divalent silver oxide cells according to the
present invention;
Figure 7 shows the relationship between the voltage stability and the storage time at room temperature for
conventional divalent silver oxide cells and divalent silver oxide cells according to the present invention;
Figure 8 shows the relationship between amount of stabilizer added to the divalent silver oxide positive electrode of a divalent silver oxide cell according to the present invention and the volume of oxygen evolved;
Figure 9 is a diagram of a circuit for measuring voltage of a divalent silver oxide cell at -1 00C;; and
Figure 10 shows the relationship between the storage time and the internal resistance for conventional divalent silver oxide cells and divalent silver oxide cells according to the present invention.
The stability of divalent silver oxide powder used for a divalent silver oxide cell according to the present invention and divalent silver oxide powder used for a conventional divalent silver oxide cell, both in aqueous alkaline electrolyte has been comparatively examined by measuring the volume of oxygen evolved using the experimental device shown in Figure 1. The volume of oxygen evolved is determined with different amounts of stabilizer being added to the divalent silver oxide powder of divalent silver oxide cells according to the present invention.
The experimental device shown in Figure 1 has a graduated glass tube 1 in which there is a 40% potassium hydroxide aqueous solution 2 and 1 g of divalent silver oxide powder 3, a thermostat 4 and a bath 5 of an aqueous solution at 400C or 60 C.
Figure 2 shows the volume of oxygen evolved with various stabilizers added to the divalent silver oxide powder. The stabilizers were cadmium oxide (CdO), tellurium dioxide (TeO2), and thallium oxide (Tl203) in amounts of 0.3%, 0.1% and 0.1% by weight respectively (calculated as the metal). It is clear from Figure 2 that a stabilizer of cadmium oxide and tellurium dioxide and a stabilizer of cadmium oxide, tellurium dioxide and thallium oxide added to the divalent silver oxide powder reduces considerably the volume of oxygen evolved compared to divalent silver oxide powder without a stabilizer.
Table 1 shows that the stability of the divalent silver oxide powder increases with other additives in addition to cadmium oxide tellurium dioxide.
TABLE 1
Additives Volume of Oxygen evolved (lIg 200 hours)
AgO none 523 CdO+TeO2 46 CdO+TeO2+PbO 14 CdO+TeO2+Tl2O3 6
CdO + TeO2 + GeO2 11 CdO+TeO2+HgO 8
In Table 1, the amount of cadmium oxide is 0.3% by weight calculated as the metal, the amount of tellurium dioxide, lead oxide (PbO), thallium oxide, germanium dioxide (GeO2), and mercury oxide (HgO) is 0.1% by weight again calculated as the metal.
It is believed that the divalent silver oxide is stable in aqueous alkaline solution since ions of stabilizer are introduced into the crystal lattice structure of the divalent silver oxide to consolidate the structure. However, the exact stabilzing mechanism remains unexplained.
Figure 3 shows the relationship between the volume of oxygen evolved with the amount of cadium and tellurium added as stabilizer to the divalent silver oxide positive electrode of a divalent silver oxide cell according to the present invention. Numerals in Figure 3 denote the volume of oxygen evolved from 1 g of divalent silver oxide in 40 KOH aqueous solution at 400C after 240 hours. The cadmium and tellurium were added to the divalent silver oxide as cadmium oxide and tellurium dioxide. Figure 3 shows that the volume of oxygen evolved is reduced as the amount of cadmium increases. The volume of oxygen eveloped is small when the amount of tellurium is within the range of 0.05 to 0.3% by weight.
The electrical capacity of a positive electrode consisting of divalent silver oxide is reduced with the addition of cadmium and tellurium in the ratio of cadmium : tellurium = 0.3% : 0.1% (cadmium: tellurium 0.34% : 0.13%) and this is the optimum to assure the required electrical capacity and to minimize the volume of oxygen evolved.
TABLE 2
AgO AgO Volume Ag2CO3 Average Apparent Apparent
content of oxygen content particle density tapping
(%) evolved (%) size (g/cc) density (ul/200hr) (it) (g/cc)
in 40KOH 40 C 98.3 16 0.41 2.96 0.79 1.95
Table 2 shows the chemical and physical properties of divalent silver oxide to which cadmium oxide, tellurium dioxide, and thallium oxide are added as stabilizer in the ratio cadmium:tellurium:thallium = 0.3%: 0.1%: 0.1% by weight calculated as the metal. It shows that a divalent silver oxide positive electrode of a divalent silver oxide cell according to the present invention has a high divalent silver oxide content and a relatively small volume of oxygen is evolved in use.Since the average powder diameter, apparent density and apparent tapping density are large, the fluidity of the divalent silver oxide powder used for the divalent silver oxide positive electrode is excellent and moulding characteristics are improved.
Figure 4 shows the relationship between divalent silver oxide content and storage time (days) of a divalent silver oxide cell according to the present invention to which cadmium oxide, tellurium dioxide and thallium oxide are added as stabilizer to the divalent silver oxide positive electrode in the ratio cadium: tellurium: thallium = 0.3%: 0.1%: 0.1% by weight calculated as the metal and divalent silver oxide positive electrode of the conventional divalent silver oxide cell having no stabilizer. A generally adopted method, e.g. potassium iodide reduction titration, is used for quantitative analysis of the divalent silver oxide content of the divalent silver oxide positive electrodes. The divalent silver oxide sample was soaked in 40% KOH solution at 600C and quantitative analysis of divalent silver oxide content was carried out every 20 days.Figure 4 shows the difference in divalent silver oxide content between the divalent silver oxide powder of a divalent silver oxide cell according to the present invention and divalent silver oxide powder of a conventional divalent silver oxide cell increases after 40 days. The divalent silver oxide content of the divalent silver oxide powder of the conventional divalent silver oxide cell is reduced to 30% after 60 days and to 10% after 80 days. On the other hand the divalent silver oxide content of the divalent silver oxide powder of a divalent silver oxide cell according to the present invention is maintained at 50% after 200 days. Thus the divalent silver oxide powder with a stabilizer of a divalent silver oxide cell according to the present invention is stable for long periods of time.
Figure 5 is a sectional view of a divalent silver oxide cell according to the present invention. The diva lent silver oxide cell has a positive electrode container 11 in which there is positive electrode material 12 coated with a reduced silver layer 13, a separator 14 and and an electrolyte absorbent layer 15. The electrolyte is an aqueous alkaline solution mainly of sodium hydroxide (NaOH). The positive electrode material 12 consists of 95-99 % by weight divalent silver oxide powder with a stabilizer and 1-5% by weight of an organic binder such as polytetrafluoride ethylene and is pressure moulded into a pellet. In the place of polytetrafluoride ethylene the organic binder may be any stable material with lubricating characteristics and organic binding characteristics necessary for pressure moulding and with acid resistance and alkaline resistant characteristics.For example, olefinic resin powders such as polyethylene and polystyrene, polyamide resin powders such as NYLON (Trade Mark), water soluble polymer powders such as carboxymethyl cellulose, polyvinyl alcohol, and polyacrylic acid soda are suitable. The organic binder may be in the form of a liquid such as a dispersion solution and not in the form of a powder.
The lower limit of the amount of organic binder is 1% by weight considering the binding effect. Although the upper limit is not especially restricted, if the amount of organic binder exceeds 5% by weight this causes a reduction of the capacity of the divalent silver oxide cell due to the reduction of the amount of divalent silver oxide powder in the positive electrode material. Further, if more than 5% by weight of the organic binder is added to the positive electrode material, the electric resistance increases and with it the internal resistance of the divalent silver oxide cell since the organic binder is an electrically insulating material.
Accordingly, the amount of organic binder is preferably 1 to 5% by weight. However, the stability of the divalent silver oxide powder does not deteriorate even if the amount of organic binder exceeds 5% by weight.
The silver layer 13 is formed by reducing the surface of the positive electrode material 12.
The divalent silver oxide cell shown in Figure 5 has a negative electrode container 11 in which there is a negative electrode material 16 consisting of mixture of amalgamated zinc powder and carboxymethyl cellulose and/or sodium polyacrylic acid. The negative electrode material is used as it is or in the form of a gel with the alkaline electrolyte. The negative electrode material may be moulded by slight pressure.
Figure 6 shows the self-discharge rate of a TR726SW cell (outer diameter: 7.8 mm, height: 2.6 mm,
Zn/NaOH/AgO) after 20 days and 40 days storage at 60 C, extracted from a thermostat bath and discharged through a 1 .5KQ load resistor to find the remaining capacity. The self-discharge rate of a divalent silver oxide cell is calculated by: self-discharge rate=(initial capacity)
~(remaining capacity after storage at 600C initial capacity x 100% The data shows the average value when n = 24.
Figure 6 shows the self-discharge rate of a divalent silver oxide cell according to the present invention after 14 months storage at room temperature compared with that of a conventional divalent silver oxide cell. The self-discharge rate of the divalent silver oxide cell according to the present invention after 40 days storage at 600C is reduced by a factor of 1/3.2 in comparison with the conventional divalent silver oxide cell. The self-discharge rate of the divalent silver oxide cell according to the present invention after 14 months storage at room temperature is reduced by a factor of 1/1.5 - 1/2.8 in comparison with the conventional divalent silver oxide cell.
The low temperature characteristics of a divalent silver oxide cell according to the present invention is shown in Figure 7. The closed circuit voltage at -10 C is the voltage when the divalent silver oxide cell is discharged for 7.8 msecthrough a load RL = 2us1. The new cell shows X of n = 10 and the conventional cell shows X of 10 lots. Figure 7 shows that the low temperature closed circuit voltage of a divalent silver oxide cell according to the present invention is low initially but the rate of change is smaller than that of the conventional divalent silver oxide cell.The reason why this rate of change is smaller is because the divalent silver oxide powder used is stable in aqueous alkaline electrolyte and the silver layer formed on the surface of the divalent silver oxide positive electrode and zinc used for the negative electrode are only oxidised to a limited extent by the oxygen evolved.
It has been found that a large current cell (Zn/KOH/AgO) according to the present invention when used in a liquid crystal display digital watch with a lamp, has a low temperature closed circuit voltage just after manufacture and this voltage is lower than that of the conventional divalent silver oxide cell by 10-100 mV and this has been found to be unacceptable. However, this problem can be overcome by: (1) Optimising the amount of stabiliser such as cadmium oxide, tellurium dioxide and thallium oxide added to the divalent silver oxide positive electrode.
(2) Eliminating silver within the monovalent silver oxide layer interposed between the divalent silver oxide positive electrode and the silver layer 13.
(3) Reducing the thickness of the silver layer 13 on the divalent silver oxide positive electrode.
Figure 8 shows the relationship between the amount of stabiliser in a divalent silver oxide positive electrode of a divalent silver oxide cell according to the present invention and the volume of oxygen involved. For curve A the stabiliser was cadmium oxide and tellurium dioxide and for curve B the stabiliser was cadmium oxide, tellurium dioxide and thallium oxide. The point at which the amount of stabiliser is zero corresponds to pure divalent silver oxide powder as used in conventional divalent silver oxide cells. Figure 8 shows that the volume of oxygen evolved for curve B is smaller than that for curve A. This is due to the addition of thallium oxide to the cadmium oxide and tellurium dioxide. In fact, the volume of oxygen evolved is a minimum when the amount of stabilizer is 5000-10000 ppm.
The stabilizer added to the divalent silver oxide powder may be either in the form of the metal or a metallic compound.
A number of divalent silver oxide cells according to the present invention were constructed as shown in
Figure 5 but with different stabilizers in the divalent silver oxide powder. These divalent silver oxide cells were TR926W (outer diameter: 9.5mm, height: 2.6mm, Zn/KOH/AgO, nominal 52 mAh) cells. The low temperature characteristics self-discharge rate and leakage occurrence rate of the cells after three months storage at room temperature are shown in Tables 3 and 4.
TABLE 3
Amount of stabilizer Low-temperature Self- Leakage
(PPM) characteristics discharge occurrence
CdO TeO2 Total (V) rate (%) rate (%)
Conventional
cell 0 0 0 1.27V 15% 30%
cellA 7 3 10 1.27V 12% 15%
cell B 65 15 50 1.27V 11% 15%
cell C 70 30 100 1.27V 10% 13% cell D 350 150 500 1.27V 10% 13% cell E 700 300 1000 1.25V 10% 13%
cell F 3500 1500 5000 1.20V 10% 12% cell G 7000 3000 10000 1.10V 10% 12%
TABLE 4
Amount of stabilizer Low-temperature Self- Leakage
(PPM) characteristics discharge occurrence
CdO TeO2 To203 Total (V) rate (%) rate (%)
Conventional
cell 0 0 0 0 1.27 15 30 cell A' 6 2 2 10 1.27 10 15
cell B' 30 10 10 50 1.27 10 15
cell C' 60 20 20 100 1.27 10 14
cell D' 300 100 100 500 1.27 9 12
cell E' 600 200 200 1000 1.23 8 10
cell F' 3000 1000 1000 5000 1.17 7 10
cell G' 6000 2000 2000 10000 1.05 8 10
In order to determine low temperature characteristics the cells were stored in a thermostat at -10 C, a switch S of a circuit shown in Figure 9 being closed and the minimum value of the closed circuit voltage within 5 seconds was read from the voltmeter V. The data shown is the average value when n= 10.
In order to determine the storage characteristics (measurement of self-discharge rate), the cells were stroed at 600C in the thermostat, removed after 40 days, discharged through a load resistor of 7.5 KQ and the remaining capacity determined. The data shown is the average value when n=24.
In order to determine leakage occurrence rate, the cells were stored in a temperature and humidity chamber at relative humidity of 90-95% and taken out after 1000 hours and evidence of leakage observed by microscope. The cells which leaked on the outer surface of the negative electrode were deemed defective.
The data shows the leakage recurrence tate when n= 100.
It is seen from Table 3 that the cells A-G are better than the conventional divalent silver oxide cell with respect to self-discharge rate and leakage occurrence rate. The self discharge rate and the leakage occurrence rate of the conventional divalent silver oxide cell is inferior because the divalent silver oxide powder which does not contain a stabilizer gradually dissolves when in contact with the aqueous alkaline electrolyte. The dissolution of the divalent silver oxide powder causes the following problems:
(1) The reduction in electrical capacity of divalent silver oxide powder.
(2) Deterioration of the separator and dissipation of the zinc negative electrode due to oxygen evolved from the divalent silver oxide powder.
(3) Increase in the internal pressure by accumulation of oxygen.
Divalent silver oxide cells according to the present invention do not suffer from these problems because of the stabilizer included in the divalent silver oxide positive electrode. The stabilizer may be in the form of oxides, hydroxides, metal powder, sulphide etc. of cadmium and tellurium with or without the addition of other components.
It has been found that the low temperature characteristics of a divalent silver oxide cell according to the present invention are closely related to the amount of stabilizer. Namely, the low temperature characteristics are reduced as the amount of stabilizier is increased. The reason for this is assumed to be that the discharge reaction of divalent silver oxide powder is difficult when discharged at a large current flows through a load resistor of RL = 200Q since the stabilizer stabilizes the divalent silver oxide powder.
A liquid crystal display digital watch with a lamp requires a voltage which is greater than 1 .05V and so it would be reasonable to regard the low temperature characteristics value of the cell F in Table 3 as the lowest limit value in view of dispersion etc. Namely, the self discharge rate and the leakage occurrence rate of divalent silver oxide cell according to the present invention may be higher than the conventional divalent silver oxide cell, while keeping the low temperature characteristics at a desired value, the amount of stabilizer being in the range of 10-5000 ppm.
Figure 4 shows the low temperature characteristics, self discharge rate and leakage occurrence rate of divalent silver oxide cells according to the present invention, the stabilizer consisting of cadmium oxide, tellurium dioxide and thallium oxide, these being varied in a similar manner to that shown in Table 3. The composition of the stabilizier is approximately in the ratio of cadmium oxide:tellurium dioxide: thallium oxide = 3:1:1.
As shown in Figure 8, the divalent silver oxide powder which includes cadmium oxide, tellurium dioxide and thallium oxide as a stabilizer is more stable than divalent silver oxide powder which includes only cadmium oxide and thallium oxide since the volume of oxygen evolved in aqueous alkaline electrolye is less.
Thus cells A' - G' are found to be better than than cells A - G with respect to the self discharge rate and leakage occurrence rate. On the other hand, the low temperature chracteristics of the cells A' - G' decrease with increase in the amount of stabilizer. The cells E' - G' have low temperature characteristics which are lower than that of cells E - G. The reason for this is assumed to be because of the different stabilizers added to the divalent silver oxide powder used for the cells E' - G' which are more stable than those used for cells E - G and that IR polarization is larger against the discharge reaction at RL = 200Q.
To yield a voltage of 1 .55V in the conventional divalent silver oxide cell a silver layer is formed on the surface of the divalent silver oxide used for the positive electrode by a reduction process and this eleminates the high electric potential difference of 1 .85V between silver dioxide and zinc. With time this silver layer changes to silver oxide since it is gradually oxidised and as a result the high electric potential 1.85V appears.
It is assumed that this disadvantage is caused by the formation of metallic silver in the monovalent silver oxide layer formed between the divalent silver oxide positive electrode and the silver layer. Therefore, electrical insulation between the divalent silver oxide positive electrode and the silver layer breaks down.
Since the silver is reoxidised, the following reaction proceeds and the internal resistance increases:
AgO + Ag < Ag2O
The following Examples of the present invention illustrate ways of producing a divalent silver oxide positive electrode from a divalent silver oxide cell according to the present invention which does not have these drawbacks.
Example 1
0.1% by weight cadmium oxide powder and 0.03% by weight of tellurium dioxide were added to 95% by weight divalent silver oxide powder and 5% by weight polytetrafluoride ethylene powder and mixed for one hour. The mixture was changed into particles and sifted and moulded by pressure at 8ton/cm3 to make pellets. The pellets were soaked in 90% by weight methanol solution including 10% KOH for 30 minutes and washed. The pellers were then soaked in 20% by weight KOH solution at 600C for 15 minutes. Finally the pellets were soaked in 50% by weight ethanol solution including 0.5% hydrazin for 3 minutes, extracted from the solution, dried at room temperature and stored in a desiccator.
Pellets with different amounts of stabilizer were made in a similar manner.
Example 2
0.01% by weight cadmium oxide powder, 0.003% by weight tellurium dioxide powder and 0.003% by weight thallium oxide powder were added to 95% by weight divalent silver oxide powder, and 5% by weight polytetrafluoride ethylene powder and mixed for 1 hour. The mixture was changed into particles and sifted and moulded by pressure of 8 ton/cm3 to make pellets. The pellets were soaked in 50% by weight methanol solution including 0.1% by weight tartaric acid and 5% by weight KOH solution for 1 hour and washed. The pellets were then soaked in 10% by weight KOH solution including 2% by weight potassium persulphuric acid for 15 minutes and thoroughly washed. Finally the pellets were soaked in 10% by weight KOH solution including 1% by weight tartaric acid for 20 minutes.After reduction, the pellets were dried at 40-50 C and stored in a desiccator. Pellets with different amounts of stabilizer were made in a similar manner.
Example 3 0.1% by weight cadmium hydroxide (Cd(OH)2) powder, 0.03% by weight tellurium hydroxide (Te(OH)e) powder and 0.03% by weight thallium hydroxide (TIOH) powder were added to 96% by weight of divalent silver oxide powder, and 4% by weight polyethylene powder and mixed for 1 hour. The mixture was changed to particles, sifted and moulded by pressure of 8 ton/cm3 to make pellets. The pellets were soaked in methanol solution including 1% KOH for 30 minutes and washed. The pellets were then soaked in 20% by weight KOH solution at 60 C for 15 minutes and washed. Finally the pellets, after soaking in 50% by weight ethanol solution including 0.5% by weight hydrazin for 3 minutes, were extracted and dried at room temperature and stored in a desiccator.Pellets with different amounts of stabilizer were made in a similar manner.
Divalent silver oxide cells (TR926W) having the construction shown in Figure 5 were made using the pellets of Examples 1 to 3 as the divalent silver oxide positive electrode. The low temperature characteristics, self discharge rate and leakage occurrence rate of the divalent silver oxide cells after storage for three months at room temperature were examined and Table 5 shows the result. As clearly seen from Table 5, cells 1 - 9 have excellent characteristics compared with conventional divalent silver oxide cells with respect to self discharge rate and leakage occurrence rate. It is seen from Table 5 that the amount of stabilizer needed to keep the low temperature characteristics at a suitable value and to reduce the self discharge rate is in the range of 10-5000 ppm.
TABLE 5 Weight%ofStabilizer Low- Self- Leakage
total weight of AgO mixture temperature discharge occurrence
characteristic rate rate (V) (%) (%) conventional - - - 1.27 15 30 cell
Example 1 CdO TeO2
0.01 0.003 1.27 10 15 1 1 2 0.10 0.03 - 1.27 8 13
3 0.39 0.13 - 1.04 7 12
Example 4 CdO TeO2 To203 0.01 0.003 0.003 1.27 8 12
2 5 0.10 0.03 0.03 1.27 7 10
6 0.30 0.10 0.10 1.02 4 8
Example 7 Cd(OH)2 Te(OH)6 TIOH
0.01 0.003 0.003 1.26 8 15
3 8 0.1 0.03 0.03 1.26 7 11
9 0.3 0.1 0.1 1.02 5 8
Figure 10 shows the variation in internal resistance of a conventional divalent silver oxide cell and a divalent silver oxide cell according to the present invention after storage at 60 C. The internal resistance of the conventional divalent silver oxide cell (curve a) increases after 40 days storage, while the internal resistance of a divalent silver oxide cell according to the present invention (curve b) scarcely changes even after 80 days storage. This is because the silver layer 13 is completely electrically insulated from the diva lent silver oxide. The complete electrical insulation of the divalent silver oxide positive electrode from the silver layer is achieved as follows. The surface of the divalent silver oxide positive electrode is treated by three processes, namely a first reduction process, an oxidation process and a second reduction process. First the surface of the divalent silver Ixide positive electrode is reduced to monovalent silver oxide (Ag2O) by a reduction process using a weak reducing agent.The surface of the divalent silver oxide positive electrode will thus be partially reduced from silver to diva lent silver oxide, the monovalent silver oxide layer being electrically conductive since it is composed of metallic silver and divalent silver oxide. Secondly, the monovalent silver oxide layer on the divalent silver oxide positive electrode is oxidized using an oxidizing agent and the metallic silver in the monovalent silver oxide layer becomes monovalent silver oxide so that the monovalent silver oxide becomes completely monovalent silver oxide and so a perfect electrical insulator. Finally the monovalent silver oxide layer is reduced to silver using strong reducing agent.In conclusion, the silver layer on the divalent silver oxide positive electrode is not oxidized by the reaction of:
AgO + Ag < Ag2O due to the complete electrical insulation of the divalent silver oxide positive electrode from the silver layer.
The divalent silver oxide cells according to the present invention and described above have excellent low temperature characteristics to prevent increase of the internal resistance and excellent storing characteristics, and leakage resistant characteristics.
In one practical embodiment of the present invention a positive electrode pellet for a TR616SWtype (outer diameter: 6.8 mm, height: 1.6 mm) cell were fabricated to produce a divalent silver oxide cell according to the present invention, a silver layer being formed on the surface of the pellet by a reduction process. The positive electrode pellet comprises cadmium oxide, tellurium dioxide and thallium oxide as stabilizer to that the divalent silver oxide powder in amounts of 0.3%, 0.1% and 0.1% by weight (calculated as the metal). In
Table 6 (A) shows the thickness of the silver layer on the pellet and (B) the amount of reduction treatment.
TABLE 6
A B
AgO Ag layerthick- Reduction treat- A/B
ness (y) ment (mAh) (Il/mAh) Invention 51 11.7 4.36
Conventional 59 7.3 8.08
As will be appreciated from Table 6 since the divalent silver oxide positive electrode of the divalent silver oxide cell according to the present invention is quite stable in comparison with the divalent silver oxide positive electrode of the conventional divalent silver oxide cell, the silver layer on the surface of the positive electrode is thinner even using the same reduction process, and the closed circuit voltage of the divalent silver oxide cell according to the present invention is much lower than that of the conventional cell by 70 100mV. Accordingly, it is found that the low-temperature closed circuit voltage is improved when the silver layer between 4.41JmAh and 8.1 p/mAh is formed on the surface of the divalent silver oxide positive electrode of the divalent silver oxide cell according to the present invention.
Divalent silver oxide cells according to the present invention have great industrial value and are applicable to pace makers, electronic watches, cameras, electronic calculators, hearing aids, etc.
Claims (11)
1. A divalent silver oxide cell comprising a negative electrode, a positive electrode, and a separator and electrolyte between said electrodes, said positive electrode consisting of a divalent silver oxide, cadmium and tellurium.
2. A cell as claimed in claim 1 in which said positive electrode includes one or more of lead, mercury, thallium, germanium, yttrium, tin, tungsten, lanthanum, rare earth element, zinc, selenium and aluminium.
3. A cell as claimed in claim 1 or 2 in which said positive electrode has a silver layer on at least part of its outer surface.
4. A cell as claimed in claim 1 or 2 in which said positive electrode is surrounded by a monovalent silver oxide layer which has a silver layer on at least part of its outer surface.
5. A cell as claimed in claim 3 or 4 in which said silver layer is formed by reducing said divalent silver oxide.
6. A cell as claimed in any preceding claim in which the positive electrode includes an organic binder.
7. A cell as claimed in claim 6 in which the components of the positive electrode other than divalent silver oxide and organic binder are present in an amount between 10 to 5000 ppm.
8. A cell as claimed in claim Sin which the relationship between the thickness (A) of the silver layer and the amount (B) of the reduction process is given by:
4.4 Fm/mAh S A/B S 8.1 um/mAh
9. A divalent silver oxide cell substantially as herein described with reference to and as shown in the accompanying drawings.
10. A divalent silver oxide cell comprising a negative electrode, a positive electrode mixture mainly of divalent silver oxide, a separator between said negative electrode and said positive electrode mixture, and an electrolyte, said positive electrode mixture containing cadmium and tellurium.
New claims or amendments to claims filed on 4 July 1983
Superseded claims 1-10
New or amended claims:
1. A divalent silver oxide cell comprising a negative electrode, a positive electrode consisting of a mixture of divalent silver oxide and metal elements including at least cadmium and tellurium, the amount of metal elements being 10 to 500 ppm by weight of said mixture, a separator between said negative electrode and said positive electrode, and an electrolyte.
2. A cell as claimed in claim 1 in which said metal elements further include one or more of lead, mercury, thallium, germanium, yttrium, tin, tungsten, lanthanum, rare earth element, zinc, selenium and aluminium.
3. A cell as claimed in claim 1 or 2 in which said positive electrode has a silver layer on at least part of its outer surface.
4. A cell as claimed in claim 1 or 2 in which said positive electrode is surrounded by a monovalent silver oxide layer which has a silver layer on at least part of its outer surface.
5. A cell as claimed in claim 3 or 4 in which said silver layer is formed by reducing said divalent silver oxide of the positive electrode.
6. A cell as claimed in any preceding claim in which the positive electrode consists of 95% to 99% by weight of said mixture and 1 to 5% by weight organic binder.
7. A cell as claimed in claim 5 in which the relationship between the thickness (A) of the silver layer and the amount (B) of the reduction process is given by:
4.4 um/mAh S A/B S 8.1 lim/mAh
8. A divalent silver oxide cell comprising a negative electrode, a positive electrode, consisting of a mixture of divalent silver oxide and metal elements including at least cadmium and tellurium, having a silver layer on at least part of its outer surface formed by reducing the divalent silver oxide, a separator between said negative electrode and said positive electrode, and an electrolyte, wherein the relationship between the thickness A of the silver layer and the amount B of the reduction process is represented by::
4.4 um/mAh < A/B < 8.1 lim/mAh
9. A divalent silver oxide cell comprising a negative electrode, a positive electrode, consisting of a mixture of divalent silver oxide and metal elements including at least cadmium and tellurium, surrounded by a monovalent silver oxide layer which has a silver layer on at least a part of its outer surface formed by reducing the divalent silver oxide, a separator between said negative electrode and said positive electrode, and an electrolyte, wherein the relationship between the thickness A of the silver layer and the amount B of the reduction process is represented by:
4.4 um/mAh S A/B S 8.1 lim/mAh 10. An oxide cell as claimed in claim 8 or 9 said metal elements further including one or more components selected from lead, mercury, thallium, germanium, yttrium, tin, tungsten, lanthanum, rare earth element, zinc, selenium and aluminium.
11. A divalent silver oxide cell substantially as herein described with reference to and as shown in the accompanying drawings.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57034950A JPS58152373A (en) | 1982-03-05 | 1982-03-05 | Silver peroxide cell |
| JP57036111A JPS58154168A (en) | 1982-03-08 | 1982-03-08 | Silver peroxide battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2119160A true GB2119160A (en) | 1983-11-09 |
| GB2119160B GB2119160B (en) | 1985-07-10 |
Family
ID=26373822
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8227135A Expired GB2119160B (en) | 1982-03-05 | 1982-09-23 | Divalent silver oxide cell |
Country Status (4)
| Country | Link |
|---|---|
| CH (1) | CH650362A5 (en) |
| DE (1) | DE3235477A1 (en) |
| FR (1) | FR2522881A1 (en) |
| GB (1) | GB2119160B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1186373A (en) * | 1982-03-29 | 1985-04-30 | Duracell International Inc. | Electrochemical cell with compacted cathode containing polyolefin powder additive |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2079522A (en) * | 1980-06-23 | 1982-01-20 | Sumitomo Metal Mining Co | Silver oxide cell |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4015056A (en) * | 1976-03-15 | 1977-03-29 | Esb Incorporated | Method of manufacturing a stable divalent silver oxide depolarizer mix |
| JPS56118266A (en) * | 1980-02-20 | 1981-09-17 | Hitachi Maxell Ltd | Manufacture of silvic-oxide battery |
| JPS57107563A (en) * | 1980-12-25 | 1982-07-05 | Sumitomo Metal Mining Co Ltd | Silver peroxide for battery |
| JPS57136770A (en) * | 1981-01-26 | 1982-08-23 | Seiko Instr & Electronics Ltd | Silver peroxide cell |
| JPS57136762A (en) * | 1981-02-09 | 1982-08-23 | Seiko Instr & Electronics Ltd | Silver(2)oxide battery |
| JPS5842171A (en) * | 1981-09-08 | 1983-03-11 | Seiko Instr & Electronics Ltd | Silver peroxide cell |
-
1982
- 1982-09-21 FR FR8215865A patent/FR2522881A1/en not_active Withdrawn
- 1982-09-23 GB GB8227135A patent/GB2119160B/en not_active Expired
- 1982-09-24 CH CH566082A patent/CH650362A5/en not_active IP Right Cessation
- 1982-09-24 DE DE19823235477 patent/DE3235477A1/en not_active Withdrawn
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2079522A (en) * | 1980-06-23 | 1982-01-20 | Sumitomo Metal Mining Co | Silver oxide cell |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2119160B (en) | 1985-07-10 |
| DE3235477A1 (en) | 1983-09-15 |
| CH650362A5 (en) | 1985-07-15 |
| FR2522881A1 (en) | 1983-09-09 |
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