A multilayer composite separator consisting of non-woven mats and ceramic particles for use in lithium ion batteries

Battery separator is a porous membrane that is placed between the positive and negative electrodes to avoid their electric contact, while maintaining a good ionic flow through the liquid electrolyte filled in its pores. Non-woven mats have been evaluated as battery separators due to their highly porous structures. In this study, composite non-woven mats were fabricated through electrospinning and lamination with a ceramic layer, and evaluated as lithium ion battery separators. The lamination with the ceramic layer provides not only improved separator dimensional stability at elevated temperatures but also the potential to increase the production rate of electrospun separators. The electrospun mats keep ceramic particles from dropping avoiding the non-uniform current density distribution caused by the loss of the ceramic particles. The composite separators enabled good ionic conductivity when saturated with a liquid electrolyte. Coin cells with this type of separators showed not only stable cycling performance but also good rate capabilities at room temperature.