The porous structure of polypropylene-based films was optimized in view of pore diameter, porosity, pore distribution and other structural factors, thereby improving the permeability of lithium ions. Application of this film as a separator in a lithium ion battery led to about 20% enhanced capacity of the cell while maintaining short circuit resistance against mechanical deformation. Furthermore, the equipment could be downsized.

JST news release, September 4, 2018