Designing thermotolerant and flame-resistant PAN-based separator via surface engineering with heteroatoms doped carbon framework encapsulated with CoS2 nanocatalysts towards safe lithium-sulfur batteries

Owing to the superior merits of high energy density, low cost and environmental benignity, lithium-sulfur batteries (LSBs) are greatly favored by researchers. However, the intrinsic shortages including serious shuttling behavior and lithium dendrites growth, are deemed as stumbling blocks on the way of commercializing LSBs. Also, the inferior thermostability and flame retardancy of common separator may cause safety hazard to LSBs. Here, the designing of thermotolerant and flame-resistant PAN-based separator (MPAN) via surface engineering with heteroatoms doped carbon framework encapsulated with CoS 2 nanocatalysts, is proposed. By utilizing MPAN separators, the efficient hinderances on shuttling behavior and marked promotions in polysulfides conversion are achieved, leading to the superior electrochemical properties. Notably, the cycling performances of LSBs under high temperature are obviously enhanced. As expected, the inhibited dendrites growth is obtained, corroborating the improved safety of LSBs. In short, this work may shed a light on constructing thermotolerant and flame-resistant separator with efficacy in suppressing shuttling behavior and lithium dendrites growth. (a) Fabrication scheme of MPAN separator; (b) Suppressing mechanism of polysulfides shuttling action and lithium dendrites growth. • A thermotolerant and flame-resistant separator (MPAN) is rationally designed. • By using MPAN separator, the shuttling behavior is efficiently suppressed. • Cycling performances of cells under high temperature are obviously enhanced. • The suppressed growth of lithium dendrites demonstrates the superior battery safety.