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US4125689A Expired / Lapsed US ⏱️ 0.0 years remaining

Positive active material for electric primary cells

Assignee: SAFT Societe des Accumulateurs Fixes et de Traction SA
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Filing: 1977-12-29
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Granted: 1978-11-14
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Expires: 1997-12-29
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Abstract

Abstract A positive active material for electric primary cells, such as are used in electronic watches, is formed from a powder composed at least partially of grains having cores of silver peroxide completely surrounded by a layer of monovalent silver oxide and covered with a thin surface layer of metallic silver. The remainder of the powder, if any, comprises monovalent silver oxide grains, also covered with a thin surface layer of metallic silver. A process for making the material includes adding a reducing agent such as hydrazine to a powder having grains of less than 50 microns in diameter of essentially pure silver peroxide and reducing the silver peroxide to the point at which a thin layer of metallic silver forms on the surface of each powder grain. This point can be detected by a substantial reduction in electrical resistivity of the powder and occurs when approximately one-half of the original powder remains as silver peroxide.

Inventors

  • 👤 Yves Jumel

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-05 23:48
CPC Classifications
H; H01; H01M; H01M4/00; H01M4/02; H01M4/36; H01M4/48; H01M4/54; Y; Y02; Y02E; Y02E60/00; Y02E60/10

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 53 words
Positive active material for primary electric cells in the form of a powder, wherein the powder comprises grains having cores of silver peroxide, each core being entirely surrounded by an intermediate layer of monovalent silver oxide, and the layer of monovalent silver oxide being covered with a thin surface layer of metallic silver.
Claim 2
Dependent Claim 53 words
Positive active material for primary electric cells in the form of a powder, wherein the powder comprises grains having cores of silver peroxide, each core being entirely surrounded by an intermediate layer of monovalent silver oxide, and the layer of monovalent silver oxide being covered with a thin surface layer of metallic silver.
Claim 3
Dependent Claim 42 words
Positive active material for primary electric cells according to claim 1 wherein the powder comprises predominantly said grains having cores of silver peroxide, and any remaining powder comprises grains of monovalent silver oxide covered with a thin surface layer of metallic silver.
Claim 4
Dependent Claim 28 words
Positive active material for primary electric cells according to claim 2 wherein said grains having cores of silver peroxide comprise approximately 50 percent by weight of silver peroxide.
Claim 5
Dependent Claim 27 words
Positive active material for primary electric cells according to claim 1 wherein said grains having cores of silver peroxide have diameters of less than about 50 microns.
Claim 6
Dependent Claim 84 words
An electric cell comprising a casing; a positive electrode contained in said casing, said positive electrode comprising a compressed powder, at least some of the grains of said powder having cores of silver peroxide, each core being entirely surrounded by an intermediate layer of monovalent silver oxide and the layer of monovalent silver oxide being covered with a thin surface layer of metallic silver; a zinc negative electrode contained in said casing; and an aqueous alkaline electrolyte contacting the grains of said positive electrode.
Claim 7
Dependent Claim 84 words
An electric cell comprising a casing; a positive electrode contained in said casing, said positive electrode comprising a compressed powder, at least some of the grains of said powder having cores of silver peroxide, each core being entirely surrounded by an intermediate layer of monovalent silver oxide and the layer of monovalent silver oxide being covered with a thin surface layer of metallic silver; a zinc negative electrode contained in said casing; and an aqueous alkaline electrolyte contacting the grains of said positive electrode.
Claim 8
Dependent Claim 18 words
An electric cell according to claim 5 comprising a separator between the positive electrode and the negative electrode.

References Cited (Backward Citations)

US4038467A Cited
US4009056A Cited
US4015056A Cited
US4048405A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1981-11-13 1982-05-15 1982-11-14 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1985-11-13 1986-05-15 1986-11-14 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1989-11-13 1990-05-15 1990-11-14 $7700.00 Window Closed / Lapsed

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