Only if the phone was designed with it as an option. It does so happen that the S5 is Qi-capable with the installation of either an OEM Samsung Qi-enabled back cover or an aftermarket charging coil. A while back I fitted my S5 with the latter, and it did work. However using the wireless charging produces heat (the energy transfer between the coils is not very efficient so what's lost turns into heat) and that's not good for the battery. I found that if I used the wireless charging regularly the result was shortened battery life, after having to replace the battery a few times I gave up on it and went back to wired charging.
Another thing to note, the Samsung Qi cover is thicker than the standard one and will prevent the use of almost every available case. This probably doesn't matter as I doubt there are any more of those covers to be had at this point in time.
