While this is just a teaser and there are still a lot of unknowns, Xiaomi did say that the device uses an array of 144 antennas transmitting millimeter-wide waves and it needs a receiving array in the form of 14 antennas. According to Xiaomi, the Mi Air Charge technology can bring 5W of power to multiple devices within a few meters.
Xiaomi also claims that physical objects do not reduce efficiency, and, hopefully, we'll see it in action pretty soon. Of course, we still need devices that have such receiving array for Mi Air Charge to work, and it is about time for a company to push for proper wireless charging technology.
Currently, there are no details on actual availability or the price, but with such device chargers for smaller devices like wearables, speakers, and even smartphones could become history.