A free-standing sulfur-doped microporous carbon interlayer derived from luffa sponge for high performance lithium-sulfur batteries

Luffa sponge, as a renewable precursor, is used for the first time to synthesize sulfur-doped microporous carbon (SMPC), which is subsequently rolled into an SMPC interlayer that acts as the polysulfide diffusion inhibitor between a sulfur cathode and separator in a Li-S battery. Instrumental analysis shows that the obtained SMPC possesses a unique microporous carbon framework, large specific surface area (3211.2 m(2) g(-1)), high pore volume (1.72 cm(3) g(-1)), good electrical conductivity (1.89 S cm(-1)) and in situ S-doping (2.72 at%). Due to the special physical properties and chemical ingredients of SMPC, the as-fabricated SMPC interlayer for Li-S batteries can not only facilitate rapid electron and Li ion transfer, but can also effectively sequester dissolved polysulfides through combining strong chemical and physical absorption. Consequently, Li-S batteries containing the SMPC interlayer deliver a high initial reversible capacity (1544.2 mA h g(-1) at 0.2C), superior rate capability (781.2 mA h g(-1) at 5C), and excellent cycling stability (over 500 cycles at 2C with 0.057% capacity fading per cycle). This eco-friendly, low cost SMPC interlayer can offer an appealing alternative for the commercialized production of Li-S cells.