Gel-based speaker shows potential of ionic conductors

A high-voltage signal that runs across its surfaces and through the layers forces the rubber to rapidly contract and vibrate, producing sounds between 20 hertz to 20 kilohertz.

Published in the August 30 issue of Science, the speaker is claimed to represent the first demonstration of electrical charges carried by ions that can be put to use in fast-moving, high-voltage devices.

‘Ionic conductors could replace certain electronic systems; they even offer several advantages,’ said co-lead author Jeong-Yun Sun, a postdoctoral fellow at the Harvard School of Engineering and Applied Sciences (SEAS).

According to Harvard University, ionic conductors can be stretched to many times their normal area without an increase in resistivity, a problem common in stretchable electronic devices. Secondly, they can be transparent, making them suited for optical applications. Thirdly, the gels used as electrolytes are biocompatible, so it would be relatively easy to incorporate ionic devices - such as artificial muscles or skin - into biological systems.