1 3 dioxolane dol

Sodium hydroxide, iron (III) chloride hexahydrate, fumaric acid, absolute ethanol (99.8%), and N,N-dimethylformamide (DMF, 99.8%) were obtained from PanReac AppliChem and used as-received. Sublimed sulfur powder (S, VWR Scientific, Hudson, NH, USA) was dried at 45 °C under vacuum overnight. Carbon black Super P (CB, Timcal, Thermo Fisher, Kandel, Germany) and polyvinylidene fluoride (PVDF, Sigma-Aldrich, Merck, Madrid, Spain) were stored at 60 °C. N-methyl-2-pyrrolidone (NMP, anhydrous, 99.5%) was supplied by Sigma-Aldrich. Lithium metal (Li, Gelon Lib, Qingdao, China, 15.6 mm diameter and 0.25 mm thick), 1,3-dioxolane (DOL, anhydrous, 99.8%, Sigma-Aldrich) and 1,2-dimethoxyethane (DME, anhydrous, 99.5%, Sigma-Aldrich) were also used as-received but stored under an Ar-atmosphere. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, Sigma-Aldrich) and lithium nitrate (LiNO₃, Sigma-Aldrich) were dried at 120 °C under vacuum for three days. Polyethylene membrane (PE, 25 µm thick, Celgard, Charlotte, NC, USA) was used as a separator and dried at 80 °C under vacuum for 3 h. Carbon cloth Gas Diffusion Layer (GDL, ELAT LT1400W, FuelCellStore, College Station, Texas, USA, 454 µm thick) was used as a substrate.

Sulfur (100 mesh, Sigma–Aldrich, St. Louis, MO, USA), Ketjenblack (Ketjenblack^®EC-600JD, AkzoNobel, Amsterdam, Netherlands), poly(vinylidene fluoride) (PVdF, KF-1300, Kureha, Iwaki, Japan, M_w = 350000), vapor-grown carbon fibers (VGCFs, Showa Denko K.K, Tokyo, Japan), Super-P (Li-conductive) (IMERYS, Paris, France), poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP, Kynar Flex^® 2801, Arkema Inc., Colombes, France), N-methyl-2-pyrrolidone (NMP, Sigma–Aldrich), 1,3-dioxolane (DOL, Sigma–Aldrich, St. Louis, MO, USA), 1,2-dimethoxyethane (DME, Sigma–Aldrich, St. Louis, MO, USA), LiTFSI (Enchem, Jecheon, Korea), Li metal foil (thickness = 200 µm, Honjo Metal Co., Osaka, Japan), and polypropylene (PP) separators (thickness = 25 μm, Celgard 2400, Celgard^®, Charlotte, NC, USA) were used as separators.