Separator coatings as efficient physical and chemical hosts of polysulfides for high-sulfur-loaded rechargeable lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) are promising alternative energy storage devices to the commercial lithium-ion batteries. However, the LSBs have several limitations including the low electronic conductivity of sulfur (5 x10(-30) S cm(-1)), associated lithium polysulfides (PSs), and their migration from the cathode to the anode. In this study, a separator coated with a Ketjen black (KB)/Nafion composite was used in an LSB with a sulfur loading up to 7.88 mg cm(-2) to mitigate the PS migration. A minimum specific capacity (C-s) loss of 0.06% was obtained at 0.2 C-rate at a high sulfur loading of 4.39 mg cm(-2). Furthermore, an initial areal capacity up to 6.70 mA h cm(-2) was obtained at a sulfur loading of 7.88 mg cm(-2). The low C-s loss and high areal capacity associated with the high sulfur loading are attributed to the large surface area of the KB and sulfonate group (SO3-) of Nafion, respectively, which could physically and chemically trap the PSs. (C) 2019 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.