Mo₂C-Embedded Carambola-like N,S-Rich Carbon Framework as the Interlayer Material for High-Rate Lithium-Sulfur...

The insulating nature of sulfur/Li₂S and heavy shuttle effect of lithium polysulfides (LiPSs) hinder the commercialization of lithium-sulfur (Li-S) batteries. To address such issues, we designed and synthesized a porous carambola-like N,S-doped carbon framework embedded with Mo₂C particles (designed as N,S-Mo₂C/C-ACF) as the interlayer material to block the polysulfide shuttle and it behaves as a catalytic mediator for LiPS conversion. The modified separator of polypropylene functionalized by N,S-Mo₂C/C-ACF, showing ultrafast wetting ability to the electrolyte and high lithium ion (Li⁺) conductivity, proves to be highly effective for inhibiting the polysulfide shuttle and simultaneously promoting the reutilization of adsorbed LiPSs. When used in Li-S batteries by coupling with a Super P/sulfur cathode, over a wide temperature range of 5-55 °C, the as-fabricated batteries delivered excellent rate capability and long cycle stability. Especially, at a high rate of 5 C, the discharge capacities of 405, 630, and 670 mA h g_s^-1 were achieved when tested at 5, 30, and 55 °C, respectively. The remarkable wide temperature performance is appealing for extended practical application of Li-S batteries.