High thermal stability multilayered electrolyte complexes via layer-by-layer for long-life lithium-sulfur battery

In this work, polyacrylonitrile/sulfonated poly(ether ether ketone) (PAN/SPEEK) composite fiber membrane as separator for lithium-sulfur battery was first prepared by electrospinning. In order to reduce the shuttle effect, multilayered polyelectrolyte complexes (CS/CNTs)(n) as surface modification agents were prepared by alternating deposition of oppositely charged hydroxylated multi-walled carbon nanotubes (MWCNTs-COOH) and chitosan (CS) via the layer-by-layer method. The as-prepared fiber multilayered complex separator (FMCS) was finally treated by heating at 120 degrees C to form cross-linked network for better thermal stability. FMCS possessed much higher porosity than that of the commercial PP separator (44%). As expected, the assembled membranes remained intact even at 150 degrees C, while PP separator shrunk severely. Compared with PP, PAN/SPEEK/(CS/MWNTs-COOH)(10) showed the discharge capacity of 956.9mAh/g at 0.1 C and maintained 463mAh/g after 100 cycles with the capacity retention rate of 48.4% which is higher than that of the commercial PP separator. Thus, this work can provide a simple method for modifying separator for long-life lithium-sulfur battery.