CoSe QDs/NiO PCNFs with built-in electric fields accelerates polysulfide conversion in lithium-sulfur batteries

Lithium-sulfur (Li–S) batteries face significant challenges, including capacity fading and restricted rate performance, primarily caused by the passivation of active materials, the polysulfide shuttle phenomenon, and sluggish redox reactions. To address these issues, a composite material comprising CoSe quantum dots (QDs)/NiO PCNFs (porous carbon nanofibers) has been designed and synthesized. This innovative design enhances the accessibility of active sites, which play a vital role in effectively anchoring and converting lithium polysulfides (LiPSs). The CoSe quantum dots (QDs) embedded in NiO porous carbon nanofibers (PCNFs) leveraged the synergistic interactions between their components to achieve exceptional cyclic stability, maintaining an ultra-low capacity decay rate of 0.034 % per cycle over 500 cycles at a current density of 2 C. The heterostructure and the built-in electric field (BIEF) work in concert to mitigate the polysulfide shuttle effect and promote faster electron and lithium-ion transport. This advanced architecture presents a promising strategy for enhancing the energy density and cycle lifespan of Li–S batteries, advancing their potential for practical implementation.