Temperature-Dependent Behavior and Shuttle Effect Suppression Using N- and O-Doped Bamboo Leaf Carbon-Modified Lithium-Sulfur Battery Separator

Lithium–sulfur (Li–S) batteries have attracted considerable attention due to their high theoretical energy density. However, the shuttle effect of polysulfides remains a major barrier to their practical application. In this study, we developed nitrogen- and oxygen-doped porous bamboo leaf biomass carbon (BLC) through a simple, cost-effective method. The porous structure and polar functional groups of BLC can effectively support the efficient capture and catalytic conversion of polysulfides, and the polar C–O bond and nitrogen heteroatoms on the surface of BLC significantly enhance its chemisorption capacity. The BLC-modified battery achieved a high initial discharge capacity of 800.96 mAh g^–1 at 2 C, and the single-cycle attenuation was only 0.239% after 480 cycles. Under a high sulfur loading (4.9 mg cm^–2), it retained a specific discharge capacity of 889.6 mAh g^–1 after 60 stable cycles. Gradient nucleation experiments from 10 to 50 °C revealed a correlation between temperature and the processes of lithium polysulfide adsorption, catalytic conversion, and passivation layer formation. Specifically, at 60 °C, the battery delivered 1000.1 mAh g^–1 and maintained excellent performance at 10 °C with a minimal decay of only 0.143% per cycle. The BLC separator enhances the solid electrolyte interphase (SEI) stability, thereby extending battery lifespan and improving cycling performance.