State-of-the-art lithium-ion batteries require a separator between the anode and cathode that not only prevents a short circuit but also allows Li-ions to flow through. Shifts in temperature can reduce the safety performance of the microporous, polymer-based separator, which could cause a short circuit and risk electrolyte inflammation. A thin ceramic separator coating made of AEROXIDE® fumed alumina reduces the thermal shrinkage and increases cell safety.

Our fumed alumina dispersions enable the preparation of ultra-thin (≤ 1 μm), homogenous ceramic coatings, which is not possible using conventional coarser particles.

Evonik offers commercial AERODISP® and experimental VP Disp. dispersion products for the preparation of reliable separator coatings. High-quality dispersion powders and our many years of expertise in dispersion chemistry means you can expect:

• stable, highly filled fumed alumina dispersions (up to 50 wt%),
• uniform and small particle size distribution (< 300 nm) and
• low viscosity for easy processing

The following table contains recommended fumed alumina dispersions for different requirements:

If you have questions about the differences between grades, or application as a separator coating, contact Evonik’s experts. Our dispersions can be specifically designed to meet your requirements.

Further information can be found here: