Developing effective heterostructure strategies to mitigate the shuttling effect and accelerate lithium polysulfide (LiPS) conversion remains a critical challenge in lithium–sulfur (Li–S) batteries. Here, we report the first carbon–free VO ₂ –VS ₂ heterostructure material synthesized via in situ sulfurization, applied as a modifier on a commercial polypropylene (PP) separator (denoted as VO ₂ –VS ₂ @PP). The as–prepared VO ₂ –VS ₂ nanorods synergistically combine the high absorptivity of VO ₂ with the efficient catalytic properties of VS ₂ , simultaneously enhancing LiPS anchoring and promoting its conversion. We systematically investigate the influence of material composition on battery performance, leveraging these functional attributes, Li–S cells incorporating VO ₂ –VS ₂ @PP exhibit exceptional cycle stability (over 500 cycles at 1C), impressive rate performance (807 mAh·g ^–1 at 5C), desirable reversibility (49.9% capacity retention after 300 cycles at 5C) and exceptional pouch cell performance (3.65 mAh·cm ^–2 after 50 stable cycles at 0.1C). This study underscores the potential of tailored heterostructures in realizing high–performance Li–S batteries, offering new insights for next–generation energy storage solutions.

Lithium-sulfur (Li-S) batteries, renowned for their exceptional theoretical energy density, are positioned as a leading candidate for future energy storage systems, offering a potential pathway to overcome the energy density limitations of conventional lithium-ion batteries. Nevertheless, the notorious lithium polysulfides (LiPSs) shuttle effect and sluggish redox kinetics hinder their practical application. To resolve these challenges, we report a novel NiO-Ni₂P/C₃N₄ heterostructure synthesized via an in-situ phosphation process. Herein, we present an in situ phosphorylation strategy for the construction of NiO-Ni₂P heterojunctions anchored on a conductive C₃N₄ substrate (NiO-Ni₂P/C₃N₄) for further integration into commercial polypropylene (PP) separator (denoted as NiO-Ni₂P/C₃N₄@PP). Mechanistic studies demonstrated that the NiO phase facilitated strong chemisorption of LiPSs, while the Ni₂P component reduced the energy barrier for Li₂S dissolution through optimised d-band electron transfer. Concurrently, the C₃N₄ framework enhanced the interfacial charge transfer and significantly reduced the charge transfer resistance. Benefiting from the synergistic "adsorption-transformation-conduction" triple-function, the cells with the NiO-Ni₂P/C₃N₄@PP separator exhibit remarkable cycling stability (over 300 cycles at 3C) and outstanding rate capability (82.5 % capacity retention after 200 cycles at 5C). This work provides atomic-level insights into the engineering of multi-step sulfur electrochemical heterostructures, providing a generic design paradigm for high-energy metal-sulfur batteries.