Device Scale (IMAGE) University of California - San Diego Caption The device is made from off-the-shelf smartphone components, which generate sound waves at extremely high frequencies--ranging from 100 million to 10 billion hertz. In phones, these devices are used mainly to filter the wireless cellular signal and identify and filter voice calls and data. Researchers used them instead to generate a flow within the battery's electrolyte. Credit David Baillot/University of California San Diego Usage Restrictions Please credit David Baillot/University of California San Diego License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.