Generally wifi devices are power hungry so a battery version is probably unlikely.  You might look at zigbee switches to see if you can integrate them into your automation system.  The zigbee switches work well on batteries but they need a hub and tend to be expensive.

Android tablets/phones, especially older ones, are quite inexpensive (a low end phone from target/bestbuy is cheaper than a TP Link switch), and make great little home autonation control panels.  You can place them where needed with a touch screen to select and control the lights, including stuck to the wall in place of or beside and existing switch or centrally in a main room.  Afternarket apps give you a variety of widgets for laying out your panel exactly how you'd like - for example a weather station, a clock, plus multiple touch/toggle button widgets for TP Link bulbs, switches or outlets.

Hello, the neutral wire is necessary now to power up the switch itself now, while we can feed back to our R&D department and they can work on it.

You can keep an eye on our official website or contatc us for further information.

Hope your understanding.