Highly porous polyacrylonitrile/graphene oxide membrane separator exhibiting excellent anti-self-discharge feature for high-performance lithium–sulfur batteries

Lithium–sulfur (Li–S) batteries have been considered as a promising candidate for next-generation energy-storage devices due to their high theoretical capacity and energy density. However, the severe self-discharge behavior of Li–S batteries strongly limits their use in practical applications. Here, we report a sustainable and highly porous polyacrylonitrile/graphene oxide (PAN/GO) nanofiber membrane separator that simultaneously enables large capacity and excellent anti-self-discharge capability for lithium–sulfur batteries. A low retention loss (5%) can be achieved even after a resting time of 24 h. Besides benefitting from the highly porous structure and excellent electrolyte wettability of the nanofiber separator, the improved performance can also be ascribed to the excellent barrier effects caused by the relatively high energy binding between –C≡N and Li2S/polysulfides and the electrostatic interactions between GO and negatively charged species (Sn2−). It is, therefore, demonstrated that this GO incorporated PAN nanofiber separator with highly porous structure and excellent electrolyte wettability is a promising separator candidate for high-performance Li–S batteries.