Ceramic Coated Separators: Influence of Nanoparticle Concentration on Thermal Properties and Coating Robustness

摘要

Lithium-ion batteries have been the battery of choice for many applications due to their high energy density, high power output, and excellent cycle life. However, large format, high energy density cells continue to pose safety concerns due to the cell chemistry and electrolyte flammability. Ceramic coated microporous polyolefin separators offer many advantages in lithium ion batteries compared to uncoated types with regard to safety and performance. In particular, high temperature dimensional stability of the ceramic coated separator offers extended protection between the positive and negative electrodes if a thermal event were to occur in the cell. This work explores the influence of nanoparticle loading level on thermal properties, moisture, and adhesive strength to the underlying substrate. Results show a path towards optimizing coating robustness and coat weight required to achieve dimensional stability, while minimizing moisture.