Battery separators

Separators play a key role in all batteries. Their main function is to keep the positive and negative electrodes apart to prevent electrical short circuits and at the same time allow rapid transport of ionic charge carriers that are needed to complete the circuit during the passage of current in an electrochemical cell. This review describes the various types of separators based on their applications in batteries and their chemical, mechanical and electrochemical properties, with particular emphasis on separators for lithium-ion batteries. The separator requirements, properties, and characterization techniques are described with respect to lithium-ion batteries. Overall, the review aims to bring into focus present and future directions of research and development in separator technologies.