Ni(OH)2 nanoflakes-decorated kelp-like porous carbon modified separator for high-performance lithium‑sulfur batteries

Lithium‑sulfur (Li S) batteries based on lithium sulfide (Li 2 S) cathodes hold great promise for next-generation energy storage devices but suffer from critical drawbacks, including lithium polysulfides (LiPSs) shuttling, sluggish redox reaction kinetics, and severe safety hazards. Here, a multifunctional separator is designed by coating a nickel hydroxide (Ni(OH) 2 ) nanoflakes-decorated kelp-like porous carbon (Ni(OH) 2 /KLPC) composite onto a polypropylene (PP) membrane. The unique KLPC skeleton derived from mucor hyphae provides a three-dimensional conductive network, while the polar Ni(OH) 2 nanoflakes offer strong chemisorption for LiPSs and high catalytic activation for the interconversion between solid-phase (Li 2 S and S) and liquid-phase (LiPSs). Meanwhile, the Ni(OH) 2 nanoflakes endow the separator with remarkable flame retardancy through an endothermic decomposition process and the formation of highly flame-retardant products nickel oxide and water. Consequently, the Li S battery assembled with the Ni(OH) 2 @KLPC modified PP (Ni(OH) 2 /KLPC/PP) separator and a Li 2 S/multi-walled carbon nanotube cathode delivers a high initial discharge capacity of 1132 mAh g −1 , remarkable rate property of 320 mAh g −1 at 5.0 A g −1 , and stable long-term cycling over 750 cycles. This work presents a promising synergistic strategy for constructing high-performance and safe Li S batteries through multifunctional separator engineering.