A multi-functional sulfurized polyacrylonitrile interlayer for lithium sulfur batteries

Abstract Functional interlayers applied in lithium sulfur batteries have been widely investigated due to its high reutilization of the diffused polysulfides and good cycle stability. However, the functional layer on the modified separator will indirectly decrease the sulfur content, which is harmful to the energy density of the whole cell. Herein, we report sulfurized polyacrylonitrile (SPAN) modified functional separator which can deliver quite a lot reversible capacity to overcome the shortage of traditional interlayer. Meanwhile, S and N dual dopants can offer abundant adsorptive sites and have strong chemisorption to polysulfides. Thus, with this modified separator, a facile sulfur cathode can deliver a high initial discharge capacity of 1338 mAh/g and merely 0.178% capacity fade per cycle over 200 cycles at 1 C. The results indicate that SPAN is a promising material for functional interlayer between cathode and separator.