Basically, a data cable will charge when connected to either a standards-conforming charger, or to a computer which will allow enough power to be drawn.

A "charger" cable is a cable that specifically has the data lines disabled and shorted out, to work with nonstandard usb chargers.

The best you could do is a cable with a switch between data and charging, but then if you connected it to a PC with the switch accidentally set to charging, you might fry your PC...