Few-Layer MoS₂-Decorated MoO₂ for High-Density Exposed Catalytic Heterointerfaces in Lithium-Sulfur Batteries

Lithium-sulfur batteries are severely limited by polysulfide shuttling and sluggish sulfur redox kinetics. Efficient catalysis in lithium-sulfur (Li-S) batteries requires not only intrinsically active catalyst materials but also catalytic interfaces with high structural exposure and electrochemical accessibility. Here, a few-layer MoS₂-decorated MoO₂ composite integrated with carbon nanotubes is developed as a functional separator coating with a high density of exposed catalytic heterointerfaces. In this composite, polar MoO₂ strongly anchors lithium polysulfides, while highly dispersed few-layer MoS₂ nanoflakes provide abundant MoO₂-MoS₂ heterointerfaces, accelerating polysulfide conversion. Meanwhile, the MoO₂-MoS₂ junction provides balanced polysulfide adsorption and pronounced charge redistribution, thereby promoting the activation and subsequent conversion of reaction intermediates. Li₂S nucleation tests and in situ x-ray diffraction further verify the accelerated kinetics of polysulfide conversion and the improved reversibility of Li₂S formation. As a result, Li-S cells deliver a high specific capacity of 1236 mAh g^-1 at 0.2 C and retain 475 mAh g^-1 after 1000 cycles at 1 C, highlighting the promise of constructing high-density exposed catalytic heterointerfaces for high-performance Li-S batteries.