Synergistic effect of oxygen-deficient Ni₃V₂O₈@carbon nanotubes-modified separator for advanced lithium–sulfur batteries

Lithium–sulfur batteries (LSBs) have attracted widespread attention due to their high theoretical energy density. However, the dissolution of long-chain polysulfides into the electrolyte (the “shuttle effect”) leads to rapid capacity decay. Therefore, finding suitable materials to mitigate the shuttle effect of polysulfides is crucial for enhancing the electrochemical performance of lithium–sulfur batteries. In this study, LSBs’ separator is modified with Ni₃V₂O₈ nanoparticles@carboxylated carbon nanotubes (Ni₃V₂O₈@CNTs) composite. There are abundant oxygen vacancies in Ni₃V₂O₈@CNTs composite which plays a synergistic effect on shuttle effect. The Ni₃V₂O₈ can tightly anchor soluble polysulfides through oxygen vacancies, while the CNTs not only facilitate the transport of ions and electrons but also weaken the migration of polysulfides, limiting shuttle effect. As a result, the cycling stability of LSBs using Ni₃V₂O₈@CNTs-modified separator has been significantly improved (with a capacity decay rate of only 0.0334% after 1500 cycles at 4.0C). This study proposes a strategy to design modified separator for high-performance LSBs.