With wireless charging all you have to do is place the smartphone on a wireless charger to initiate charging. Of course, the wireless charger itself must still be plugged into the wall. The technology is based on the principle of electromagnetic induction
iPhones and Samsung Galaxy SIII can also be wirelessly charged using the Powermat’s wireless charger. Powermat is a proprietary standard that comes from Duracell.
Nokia Lumia 920, Samsung Galaxy S4 and Google Nexus 4 support Qi standard of wireless charging developed by Energizer. There are inductive sleeves available for iPhone and BlackBerry as well.