We don't have a battery powered WiFi Thermostat, but we do have wireless thermostats that can be controlled from an app.
The neoAir Kit works with the neoHub and our wireless receiver RF Switch. The neoHub is connected directly to your router and the wireless neoAir can be placed on a desk stand or mounted on the wall and this communicates wirelessly to the neoHub and the RF Switch
The benefit of this solution is you can pair up to 32 thermostats to the neoHub. You can see this kit here.
Another solution is the neoHub Mini OT or neoHub Mini HW. These are designed for smaller systems, such that up to 2 neoAir can be paired to the neoHub Mini.
The neoHub Mini OT supports OpenThem whereas the HW model offers up to 2 zones of heating and hot water control. Both neoHub Mini models connect via WiFi to your broadband router. You can see the two neoHub Mini kits here