Lots of people have written about eliminating the last wire now that we have wireless mice, keyboards, and network connections – the power cord. I have often thought, “that would be cool”, but really, I haven’t ever found the power cord that much of a problem. Until now.
The transformer on my tablet’s power cord is dead. I went looking for a replacement today, only to find that almost every laptop power cord is proprietary! For an industry with pretty good standards, like IDE, USB, etc, I was surprised! And annoyed. Because of the fact that you must order replacements from the manufacturer, they charge insane prices. And because there are so many, stores do not carry them in stock, which means big delays for ordering the parts. I am going to try to find a universal one (from Targus perhaps) but who knows.
Which leads me to believe that we might always be tethered. Power cords have been around since probably electricity was invented, and yet we don’t have a standard for computers. How on earth are they going to settle on a standard for wireless power? Unlikely, and that’s unfortunate.
MasterMaq's Blog 
If a battery-less crystal radio with an ear bud could be build 30+ years running on the energy on radio waves back then – I wonder what kind of ‘EMF-in-the-air charger’ could be built today.