Forgot to say that you should definitely first pgrade to the latest Z-Stack Zigbee Coordinator firmware if you are using ITead’s “Sonoff Zigbee 3.0 USB Dongle Plus” (model “ZBDongle-P” based on Texas Instruments CC2652P - ITead's "Sonoff Zigbee 3.0 USB Dongle Plus" (model "ZBDongle-P") based on Texas Instruments CC2652P +20dBm radio SoC/MCU as later Z-Stack Zigbee Coordinator firmware have many bug-fixes → Z-Stack-firmware/coordinator at master · Koenkk/Z-Stack-firmware · GitHub
You should just need to factory reset the device and then delete the device from inside ZHA UI.
Then the standard procedure for troublesome devices is just to try re-paring it over and over again. See → https://www.home-assistant.io/integrations/zha#best-practices-to-avoid-pairingconnection-difficulties (and related steps here → https://www.home-assistant.io/integrations/zha#how-to-add-support-for-new-and-unsupported-devices)
Tthat assumed that you are already following the best practices → https://www.home-assistant.io/integrations/zha#zigbee-interference-avoidance-and-network-rangecoverage-optimization
Again, suggest start by replacing the battery and make sure follwing best practices before trying to re-pair the device again and again → Zigbee networks: how to guide for avoiding interference and optimize for getting better range + coverage
I too prefer Z-Wave for battery-powered devices, but I have had some problems with such as well 