As of my last knowledge update in September 2021, flexible zinc-hybrid batteries, such as zinc-manganese dioxide batteries, typically have a nominal voltage of around 1.5 volts. This voltage is consistent with the chemistry of the battery and is the same as standard disposable alkaline batteries. However, keep in mind that battery technology is constantly evolving, and there might have been developments or changes since then.
If you're looking for the most up-to-date information on a specific type of battery, I recommend checking with manufacturers, scientific publications, or industry reports for the latest specifications.