China’s new additive makes EV lithium-metal battery last 3,000 cycles

Researchers at Southeast University in China have developed a novel electrolyte additive, 1,3-dithiane, that significantly enhances the lifespan and safety of lithium metal batteries (LMBs), a promising next-generation energy storage technology. The additive, a thioether-based compound with a high sulfur content (53.5%), stabilizes the battery’s electrode interfaces by forming a sulfur-rich protective layer through a chemical process called polarity inversion. This layer converts unstable organic components into stable sulfur-based inorganic compounds and protects the electrolyte solvents, resulting in a more reliable solid electrolyte interphase (SEI). By strengthening the SEI, 1,3-dithiane suppresses lithium dendrite growth and slows capacity loss, enabling over 3,300 charge-discharge cycles in lab tests. Additionally, 1,3-dithiane optimizes both the kinetics and thermodynamics of the battery system. Its strong redox properties and preferential adsorption facilitate the formation of a dynamic, inorganic-rich interphase with high ionic conductivity