New Chinese solid-state EV battery coating runs 7,000 hours at -22°F

Researchers from Tsinghua University’s Shenzhen International Graduate School and Tianjin University have developed a novel “flexible armor” coating for solid-state electric vehicle (EV) batteries that significantly enhances their durability and performance in extreme cold. Unlike traditional lithium-ion batteries that use flammable liquid electrolytes, solid-state batteries employ solid electrolytes, offering safer and potentially longer-lasting power sources. However, these batteries have historically suffered from cracking and degradation under rapid charging and freezing temperatures. The new coating, made from silver-based materials (Ag₂S and AgF), forms a flexible solid electrolyte interphase (SEI) layer that can bend without breaking, maintaining structural integrity and allowing smooth lithium-ion movement. Laboratory tests demonstrated that batteries with this flexible coating could operate continuously for over 4,500 hours under high-stress conditions and maintain stable performance for more than 7,000 hours at –30°C (–22°F), temperatures that typically damage conventional solid-state cells. The researchers drew inspiration from natural structures