"good battery life" - battery powered cameras which are not hooked up to solar panels will quickly run down if you're doing any significant video streaming.
Most of the popular consumer products which are "wirefree" - that is battery for power + wifi for data are cloud products which are "locked down", that is without an available RTSP feed from the camera itself.
What are you attempting to accomplish?
Some do custom DIY hacks to power wifi cameras that have rtsp feeds with batteries / solar panels - or even an IP PoE camera, and connect a wifi bridge to the camera.