Functionalized polyolefin separators

Abstract

Lithium-ion batteries have emerged as a dominant energy storage device for utility electronics and transportation. Typically, the lithium-ion batteries encompass electrochemically active component anode and cathode wetted with an electrolyte solution, which are physically separated through a polymer membrane known as a separator. Although the separator membrane is a passive component, it plays a significant role in determining the cycle life, energy density, and safety of a battery. Polyolefin-based membranes are widely used separators in lithium-ion batteries due to their good mechanical strength, chemical inertness, low cost, and thermal stability. This chapter discusses the properties, requirements, preparation, characterization techniques, and performance evaluation of polyolefin-based separators for lithium-ion batteries. The structure-electrochemical properties of the commercial polyolefin and modified polyolefin separators are discussed. Finally, challenges in the polyolefin-based separator membranes for the development of advanced lithium-ion batteries are discussed in detail. © 2025 Elsevier Inc. All rights reserved.