Mitigating polysulfide shuttling and volume expansion in advanced lithium–sulfur batteries via ZnSe/CoSe2 heterojunctions embedded in N-doped carbon and carbon nanotubes

Lithium–sulfur (Li–S) batteries are promising for next-generation storage, but their practical deployment is critically hindered by the polysulfide shuttle effect, the intrinsic low conductivity of sulfur, and severe volume expansion during cycling. In the study, the CNT-ZnSe@NC-CoSe 2 composite was fabricated through high-temperature selenization of a co-precipitated CNT-ZIF8 precursor that had been coated with polydopamine and chelated with Co 2+ ions. The ZnSe/CoSe 2 heterojunctions accelerate LiPS conversion and guide uniform Li 2 S deposition. An N-doped carbon shell buffers volume expansion and boosts catalysis, while interconnected CNTs form a robust 3D conductive network for rapid transport. This synergistic architecture suppresses the shuttle effect, ensuring stable long-term cycling for advanced lithium-sulfur batteries. Consequently, the S/CNT–ZnSe@NC–CoSe 2 cathode delivers an initial capacity of 1063.1 mAh g −1 at 0.1C and retains 355.2 mAh g −1 at 3C. Notably, it maintains a stable capacity of 577.2 mAh g −1 after 200 cycles. This work presents a heterostructure with enhanced polysulfide anchoring and efficient electron transport, paving the way for the development of high-performance lithium–sulfur batteries.