Low-pressure ethane/nitrogen gas mixture plasma surface modification effect on the wetting and electrochemical performance of polymeric separator for lithium-ion batteries

•The C2H6/N2 plasma improves the wettability of the polymeric separator.•Effects of plasma treatment factors on separator were studied.•The polar functional groups from PCVD cause increased surface energy of separator.•The C2H6/N2 PCVD can be used as the effective surface modification for separator.

The wettability and electrochemical performance of polymeric separator can be modified by ethane/nitrogen gas mixture plasma chemical vapor deposition. The static water contact angle of the plasma-modified polymeric separator notably decreased with varying treatment time and plasma power. Furthermore, the plasma modified polymeric separator surface was detected by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The surface analyses demonstrate that the improved wettability of the polymeric separator resulted from the increased polar component of surface energy. In addition, the electrochemical characteristic of plasma-modified polymeric separator shows the improved performance in electrochemical impedance spectroscopy measurement. The experimental results show the important role of chemical species in the interaction between ethane/nitrogen gas mixture gas plasma and a separator surface, which can be controlled by surface modification to tailor the wettability and electrolyte retention.