While the ppt is correct, one important point is missing: electronic devices like mobile phones are NOT designed to survive in a strong electromagnetic field being radiated upon them. Try it if you dare, and your phone can or cannot survive!
To charge a battery, use the proper power supply delivered with your cell phone, and plug the cable where it belongs. It is simple and 100% efficient. If you decide to try the induction coil, RF or microwave method, such devices are highly inefficient, and work over short distances only, like 10-20 cm (4-8 inches). If you happen to use a frequency to which mobile phone components are sensitive (the receiver is a double-conversion superhet), the RF or microwave power can kill an important component quite fast.
Do what you want; I deem it foolish but be aware of the problems!