Positive active material for electric primary cells
US4125689A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 29, 1977 |
| Grant date | Nov 14, 1978 |
| Priority date | — |
| Expiry date | Dec 29, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E60/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.