Breakthrough in battery tech: Ultra-thin coatings extend solid-state battery life by 28%

A new study from Hanyang University has uncovered a key breakthrough for more durable batteries. Researchers found that ultra-thin protective coatings on cathodes can drastically improve the lifespan of sulfide-based all-solid-state batteries (ASSBs). The findings offer a solution to one of the biggest challenges in battery technology—interface degradation between cathode materials and solid electrolytes. Sulfide-based ASSBs are seen as a safer and more stable alternative to traditional lithium-ion batteries. However, their performance often suffers due to chemical incompatibility at the interface between cathode active materials and solid electrolytes. This issue leads to side reactions that shorten battery life and reduce efficiency.

The research team, led by Professor Tae Joo Park, focused on lithium niobium oxide (LNO) as a protective coating for NCM811 cathode powders. Using a rotary-type powder atomic layer deposition (ALD) technique, they applied LNO layers of varying thicknesses—1 nm, 2.5 nm, and 5 nm. The results showed that coatings of at least 2.5 nm were necessary to maintain interface stability without blocking lithium-ion movement. Cells with the thinnest 1 nm coating initially delivered the highest discharge capacity but degraded much faster over time. In contrast, the 2.5 nm and 5 nm coatings extended cycle life by roughly 28%, proving that thicker layers better prevent side reactions. The study also demonstrated that powder-ALD can produce these coatings with high precision, making it a viable method for large-scale battery production.

The findings confirm that precise, ultra-thin coatings can significantly enhance the durability of ASSBs. With this method, manufacturers could produce longer-lasting, higher-performance batteries for applications like electric vehicles. The research highlights powder-ALD as a scalable solution for next-generation battery materials.