Lithium dendrites snap like glass in batteries, exposing hidden risks and failure mechanisms in next generation energy storage systems.
Scientists have, for the first time, captured real-time footage of lithium dendrites snapping inside a working battery, revealing a critical weakness that could reshape future battery design. The research, led by Yan Yao at the University of Houston, challenges long-standing assumptions about how lithium behaves under operating conditions.
Lithium dendrites are tiny, needle-like structures that form during repeated charging cycles. They have long been associated with short circuits and fire risks, particularly in high-energy batteries. However, they were widely believed to be soft and ductile, meaning solid-state electrolytes could easily block their growth.
The new findings overturn that belief. Instead, dendrites behave more like brittle, rigid materials that can “snap like glass.” This mechanical strength allows them to grow as stiff, needle-like structures capable of piercing internal battery components, including separators and electrolytes.
Using advanced operando scanning electron microscopy, researchers directly observed dendrites forming and breaking in real time inside an active solid-state battery. This required a specialized air-free chamber that enabled imaging without disrupting battery operation, offering an unprecedented look at dendrite behavior.
Despite being only hundreds of nanometers wide, over 100 times thinner than a human hair, these structures are surprisingly robust. Their strength comes from a nanoscale single-crystal lithium core, reinforced by a surface layer formed during battery operation. This combination allows dendrites to maintain their structure as they grow, increasing the risk of internal damage.
The study also sheds light on why dendrites form in the first place. Factors such as fast charging and low temperatures can accelerate their growth, making them a persistent safety challenge even in next-generation solid-state batteries.
These insights suggest that relying solely on solid electrolytes may not be enough to prevent dendrite-related failures. Researchers propose alternative strategies, including lithium alloy anodes and improved material design, to better resist penetration and fracture.
By revealing the true mechanical nature of lithium dendrites, the study marks a significant step toward safer and more reliable energy storage systems for electric vehicles, electronics, and grid applications.
