Great potentials of lignin-based separator for Li-ion battery with electrospinning in aqueous system

Abstract Separator plays a key role in the safety and performances of lithium-ion batteries with the needs of good thermal stability and wettability. Compared with the commercial separator mainly made by polyolefins in organic solvents, the electrospinning of lignin/polyvinyl alcohol in an aqueous solution has been investigated as a green and economically viable method to produce high-performance separators without any other chemical additives. Lignin/polyvinyl alcohol (mass ratio: 3:7) nanofiber separators outperform commercial polypropylene separators in terms of porosity (71 %), liquid absorption (373 %), and outstanding thermal stability at 200 °C. Additionally, Li-ion battery cells that were constructed using different separators were assessed to demonstrate favorable electrochemical performance. The results showed that fabricated Li-ion battery with Lignin/polyvinyl alcohol (mass ratio: 3:7) nanofiber separators possesses a superior capacitance of 154.1 mA h g−1 at 0.5 C, and maintained outstanding cycle stability after 50 times of charging and discharging process at 0.5 C with the capacitance retention rate up to 98.7 %. The facile and sustainable synthesis strategy of lignin-based separator materials for Li-ion batteries developed in this work provides new perspectives for related research, especially based on environmentally friendly aqueous systems.