N-doped carbon-coated halloysite loaded with transition metal sulfide for synergistic polysulfides adsorption and conversion in Li-S batteries

Provides a novel strategy utilizing mineral to synthesize high-performance sulfur host. • HNT@NC-MS 2 (M = Co, Ni, Fe) exhibit superior anchor and catalytic abilities for LiPSs. • HNT@NC-CoS 2 /S battery exhibit outstanding rate performance and cycle stability. • HNT@NC-CoS 2 shows broad application prospects in practical high-performance LSBs. Lithium-sulfur batteries (LSBs) are impeded by the shuttle effect arising from soluble lithium polysulfides (LiPSs) and the sluggish kinetics of sulfur redox reactions. To tackle these issues, we designed a ternary sulfur host comprising hollow tubular halloysite (HNT) coated with N‑doped carbon layer and decorated with transition metal sulfide (CoS 2 , NiS 2 , or FeS 2 ) nanoparticles via high‑temperature carbonization and in situ solvothermal synthesis. The hollow nanotubular structure of HNT provides space for sulfur loading and volume accommodation, the carbon shell ensures electrical conductivity, and the MS 2 nanoparticles offer polar sites for LiPSs chemisorption and catalytic conversion. Among the three sulfides, CoS 2 exhibits the strongest catalytic activity, particularly in accelerating the liquid‑phase conversion of long‑chain Li 2 S 8 to short‑chain Li 2 S 4 . Benefiting from this synergy, the HNT@NC-CoS 2 /S cathode delivers an initial capacity of 1018.4 mAh g −1 at 0.5 C with 81.5% retention over 200 cycles. At a high sulfur loading (3.5 mg cm −2 ) and a lean electrolyte-to-sulfur ratio (E/S ≈ 10 µL mg −1 ), the cell demonstrates high areal capacity of 3.1 mAh cm −2 after 50 cycles while delivering enough energy to illuminate an LED for approximately 30 min. This work provides a rational pathway for constructing adsorption‑catalytic integrated sulfur hosts and promotes the value‑added utilization of clay minerals in energy storage. Download: Download high-res image (282KB) Download: Download full-size image