We already have devices that charge without plugging them in, but the devices must be laid right on top of a special coil.
How it works
The technology is called "magnetic resonators". A loop or coil of conductive material like copper, carrying an
alternating current (AC), is a very efficient structure for generating
or capturing a magnetic field. If a conductive loop is connected to an
AC power source, it will generate an oscillating magnetic field in the
vicinity of the loop. A second conducting loop, brought close enough to
the first, may “capture” some portion of that oscillating magnetic
field, which in turn, generates or induces an electric current in the
Resonant Magnetic Coupling: Magnetic coupling occurs
when two objects exchange energy through their varying or oscillating
magnetic fields. Resonant coupling occurs when the natural frequencies
of the two objects are approximately the same.
Late 1800s: Tesla drew up plans for a
tower, about 57 meters tall, that he claimed would transmit power to
points kilometers away, and even started to build one on Long Island.
Though his team did some tests, funding ran out before the tower was
2006: WiTricity gets more attention. List of articles here.
June 2007. A study: "Wireless Power Transfer via Strongly Coupled Magnetic Resonances". Science magazine.
2008: Marin Soljacic powered a 60-watt lightbulb from 2 meters away.
WiTricity Corporation is selling wireless technology. Marin Soljacic is on the board and is the founder.
I was unable to find an update on if they have increased the distance between the resonators (units). If you have more recent info that the witricity can be transmitted more than 2 meters, please leave a comment below.
MIT News. June 7, 2007.