Silver Oxide Button Cells
The primary (non-rechargeable, disposable) Silver Oxide button cell is the highest voltage non-lithium type. Cells have an initial voltage of 1.6V. This declines in the first 5-10% of its life to 1.55V, which it then holds until the last 1% of its life. These cells are long lived, and maintain a very stable voltage for about 96% of their lives. The traditional Lithium coin cells are 3V (or 3.6V for low current long life backup type).
Only the Zinc Air button cells have a greater capacity (in this range1) but lower voltage of 1.4V initially and then 1.35V most of the life. But they can’t be in a sealed device and will run flat in 2 weeks to 4 weeks as soon as the seal is opened to the air. The Silver Zinc may operate on an intermittent basis for many years and in a totally sealed device such as a diver’s watch.
1. Lithium cells are possibly higher energy density, but 3V or 3.6V.