Fabrication of a Light-Weight Dual-Function Modified Separator towards High-Performance Lithium-Sulfur Batteries

A light-weight dual-functional modified separator for lithium–sulfur batteries is prepared through a physical blend and blade-coating approach. The separator is coated with carbon black/poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (CB/PEDOT:PSS), remarkably improving the utilization of sulfur by serving as the co-current collector. Moreover, the PEDOT:PSS effectively inhibits the diffusion of polysulfides and promotes the migration of lithium ions by providing chemical absorption and cation transport acceleration. When assembling this modified separator into the coin cell, an initial specific capacity of 1315 mAh g⁻¹ at 0.2 C is achieved with a capacity of 956 mAh g⁻¹ after 100 cycles, showing a superior performance compared to the cell without an interlayer. Meanwhile, the cell exhibits a rate capability with a discharge capacity of 699 mAh g⁻¹ at a current density of 2 C. Notably, the areal density of CB/PEDOT:PSS coating is as low as 0.604 mg cm⁻², bringing a specific electrode capacity of 522 mAh g⁻¹ at 1 C.