UW Battery-Free Cellphone (IMAGE) University of Washington Caption UW engineers have designed the first battery-free cellphone that can send and receive calls using only a few microwatts of power. Credit Mark Stone/University of Washington Usage Restrictions With credit 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.