AEROXIDE® as separator filler improves the safety of Lithium-ion battery cells
The Challenge
The separator is a crucial element in cells of Lithium-ion batteries (LIB): A porous, polymeric membrane made of PE or PP separates the electrodes from each other to prevent a short circuit.
A separator should be as thin and as safe as possible. Besides ceramic coating of separators, the LIB industry works on an alternative concept: the ceramic filling of separators. It is a way to design polymer membranes even thinner, while maintaining the good safety properties of a thicker separator. However, the nature of the ceramic filler is very important for the final performance of the separator.
Evonik’s Smart Solutions
The industry uses two different production routes for ceramic-filled separators: a dry process and a wet process. The dry process combines metal oxide powder and a polymer with focus on PP. The wet process combines metal oxide powder, oil, and a polymer with focus on PE.
Evonik Smart Effects offers matching AEROXIDE® fumed alumina products for both production routes. The advantage for producers is that they need less of the ceramic ingredients, compared to other metal oxide particles. The reason is that the nano-structured aggregates of AEROXIDE® act as a strong backbone in the final membrane, even in a lower concentration.
