does a battery operated wifi extender/booter exist?

Hi

I am looking for a battery operated/chargeable network wifi extender.  I have a shed with no power but I have cameras that can operate with current wifi but not with 100% reliability

I would like to purchase a battery operated or chargeable wifi extender if such a device exists - I have looked online and amazon, and even when they come up in the search they still need a power outlet

anyone know of any such device?

thanks

g