Only AC powered Z-wave devices function as repeaters. This would include Z-wave switches, outlets, and plug-in receptacles. There are dedicated z-wave repeaters, but they are essentially a compact plug-in receptacle without an outlet. My preferred setup is to install a z-wave switch near the door that operates either the interior or exterior light.
Anything that operates solely on battery power (e.g. a PIR motion sensor, lock, or window/door sensor) would have a dramatically shortened battery life if it also functioned as a Z-wave repeater that was constantly listening in a high power state.