Dynamic Ni–N4 centers enable concurrent polysulfide catalysis and Li+ flux control for high-performance Li–S batteries

This work introduces nickel (II) tetraphenylporphyrin (NiTPP) as a multifunctional electrolyte additive to simultaneously address polysulfide shuttle and uncontrolled lithium dendrite growth in lithium–sulfur (Li–S) batteries. Mobile NiTPP species act as homogeneous catalysts with Ni–N 4 centers for rapid polysulfide redox mediation to suppress migration, while planar molecules featuring lithium-affinity capability migrate to the lithium metal surfaces, enabling uniform lithium flux and anode protection. NiTPP-modified electrolytes significantly enhance Li–S battery performance, demonstrated by 634.9 mAh g −1 at 4C, 758.3 mAh g −1 after 100 cycles at 0.2 C (83.4% retention), and 757.5 mAh g −1 under high sulfur loading (2.9 mg cm −2 ) with lean electrolyte ( E / S = 5 μL mg −1 ), all with high Coulombic efficiency. Crucially, NiTPP, acting as a soluble dual-functional mediator enabling homogeneous operation in electrolytes, simplifies Li–S battery fabrication while demonstrating the commercial viability of molecularly engineered mobile active sites for stabilizing both electrodes in high-energy-density Li–S batteries.