wireless chargers are good but they still need a man-produced power source. Which is called "hot power" by the electrical minded. "cold electricity" is ambient electricity thats the kind harnessed from the air. That would make wireless chargers self powered :)
i found this earlier today it shows a basic introduction into harnessing free energy if anyone gets curious enough to play with it https://www.instructables.com/id/Free-energy-generators/