Recent progress in polyetherimide membrane for high-performance lithium batteries

Electrical energy is an indispensable part of life, especially for mobile phones, laptops, cars, hybrid electric vehicles, and other electronic devices. Behind the evolution of electronic devices, lithium-ion batteries (LIBs), which provide the high energy density required for modern devices, have played a crucial role. The LIB is considered the heart of portable electronic devices. It comprises the cathode, anode, and separator, preventing physical contact between the cathode and anode and keeping the flow of ionic movement between the two sides of the membrane separator. Although the separator does not participate in the charge-discharge process, it profoundly affects the battery performance, for instance, safety, ionic movement, lifespan, and overall performance parameters. Among the separators, polyolefin separators, especially polypropylene, and polyethylene, have been used widely despite their disadvantages, including low performance, low thermal stability resulting in an explosion, dendrite growth preventing ionic movement in the long run, and low melting point, making them unable to be used in harsh environments. Conversely, polyetherimide (PEI) membrane separators stand out compared to other separators in the case of overall performance. PEI is considered the potential separator, providing higher safety, high thermal resistance, a low thermal runway, and balanced wettability for better performance. We encompass this review paper into four sections: firstly, it discusses the requirements for the separators, secondly the preparation and the fabrication methods of the PEI membrane separator, thirdly applications of the PEI separators, and finally it focuses on the current research gap existing on the PEI separator. Moreover, future directions are provided for commercial production, performance enhancement based on various factors, environmentally friendly and low carbon footprint materials for battery components, and future applicability for LIBs.