A research team at Harvard has created a remarkable proof of concept device: a thin, transparent speaker powered by ions instead of electricity. Such "ionic devices" could lead to artificial muscles, telescopic contact lenses, and more.
In the electronics we use every day, a constant flow of charged electrons that we call electricity provides power for circuits, LCDs and motors. Ionic devices are powered not by electrons, but as you might guess, ions. These tiny charged particles have several advantages over electrons.
Electrons flow quickly and easily (so much so that, we think of them like a fluid on tap), but basic physical limitations mean you're unlikely to have a transparent cable or flexible circuit board.
Ionic conductors, on the other hand, stretch and compress without a problem, and with the ions suspended in a water-based "hydrogel," the resulting devices can be as clear as glass.
The problem, as scientists have known for years, is that ionic particles are slow and heavy compared to the nimble electron, and high voltages can cause reactions and enough heat to burn away the whole setup. The Harvard team, led by professor Zhigang Suo, managed to avoid these issues altogether.