Binder‐Free Nanoparticulate Coating of a Polyethylene Separator via a Reactive Atmospheric Pressure Plasma for Lithium‐Ion Batteries with Improved Performances

A reactive atmospheric pressure plasma containing Ar/O 2 /hexamethyldisiloxane is applied to coat polyethylene (PE) separators for lithium‐ion batteries. The PE separator moves through the plasma region roll‐to‐roll, and its top and internal fiber surface is coated with a thin SiO x C y H z film composed of nanoparticulates with an average size of ≈100 nm. The nanoparticulate film has relatively high heat resistance, which provides a PE separator capable of structural support with improved thermal stability. Meanwhile, the polar functional groups on the PE surface improve its crucial properties such as wettability, electrolyte uptake, and ionic conductivity. A mere 3 min of coating endows the lithium‐ion battery with a lower interface resistance and improved C‐rate and cycling performances. Most importantly, the binder‐free coating method provides a new, eco‐efficient way to improve the performances of polyolefin separators for lithium‐ion batteries.