▎ 摘　　要

Lithium-sulfur (Li-S) batteries are regarded as a potential next-generation energy storage system but they are hampered by low active-material utilization, polysulfide shuttling, and rapid capacity fade. We present here the use of lightweight boron-and nitrogen-doped reduced graphene oxide (B-rGO, N-rGO) coated separators to suppress polysulfide diffusion and enhance active material utilization at high sulfur contents. B-rGO and N-rGO are synthesized through a facile modified Hummer's method involving the exfoliation of graphite sheets. Upon reduction, the carbon forms valuable interlayers with dynamic spacings for polysulfide trapping. Freeze-drying is utilized to preserve the structure of the pillow-like carbon, which is then slurry-coated onto a separator and placed against.a sulfur cathode. The advantages of boron and nitrogen and their affinity towards polysulfides is compared while noting the lighter carbon coatings with good electrochemical stability. The cells attain a loading of 4.0 mg cm(-2) with a high sulfur content of 66.5 +/- 0.5 wt % on including the weight of the coatings. After a long cycle life of 400 cycles, N-rGO and B-rGO are still able to maintain a specific capacity of, respectively, 430 mA h g(-1) and 367 mA hg(-1) (C) 2017 Elsevier B.V. All rights reserved.