Hemispherical mesoporous hollow carbon nanobowls as a separator-cum-cathode material for enhanced sulfur redox kinetics and polysulfides regulation in Lithium-sulfur batteries

Lithium-sulfur batteries (LiSBs) are promising next-generation energy storage systems owing to their high theoretical energy density; however, their practical application is hindered by sluggish sulfur redox kinetics, severe polysulfide shuttling, and the structural degradation of sulfur hosts. Herein, we report the use of hemispherical mesoporous hollow carbon nanobowls (HM-HCNBs) as a multifunctional platform that simultaneously serves as a high-efficiency sulfur host and functional interlayer for modified separators. The hollow and mesoporous architecture of HM-HCNBs provides a high sulfur-loading capability, robust structural stability, and efficient charge transport, while functionalization with Mo–V–S introduces abundant polar catalytic sites that strongly anchor soluble polysulfides and promote their reversible conversion to polysulfides. Systematic electrochemical evaluation demonstrated that Mo–V–S@HM-HCNBs/Celgard-based LiSBs exhibited significantly enhanced reaction kinetics, reduced polarization, and accelerated Li⁺ diffusion compared to pristine Celgard and HM-HCNBs-only separators. The optimized cell delivered a high discharge capacity of 1387 mAh g⁻¹ at 0.1 C, superior rate performance with ∼51.2 % retention at 5 C, and excellent long-term cycling stability, maintaining 84.9 % of its initial capacity after 200 cycles with a low decay rate of ∼0.073 % per cycle, and sustaining a stable performance over 1000 cycles at 3C. Morphological analyses further confirmed the effective suppression of polysulfide migration, preservation of separator integrity, and homogeneous lithium deposition without dendrite growth during cycling. These findings establish a separator-cum-cathode concept that integrates physical confinement, chemical anchoring, and catalytic acceleration within a single platform, offering a versatile strategy for overcoming the key limitations of LiSBs and paving the way for high-performance and durable next-generation energy storage systems.