Safety evolution of Li-S batteries (IMAGE) Particuology Caption The violent exothermic reactions between high-order polysulfide rather than lower-order polysulfide and dendritic Li push the cycled Li–S pouch cells into thermal runaway. Credit Fengni Jiang, Taiyuan University of Technology Usage Restrictions News organizations may use or redistribute this image, with proper attribution, as part of news coverage of this paper only. License Original 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.