Trimetallic synergy-enhanced multidimensional composite separator for high-rate lithium-sulfur batteries

The practical application of lithium‑sulfur (LiS) batteries is often restricted by the uncontrolled diffusion of lithium polysulfides (LiPSs) and their intrinsically sluggish redox kinetics. To address these limitations, we designed a multidimensional composite separator by anchoring Zn-Co-Ni-S nanocrystals onto alkalized two-dimensional transition metal carbide/nitride (MXene) nanosheets, followed by the incorporation of one-dimensional carbon nanotubes (CNTs), yielding a robust and highly conductive interfacial architecture. This multidimensional configuration combines physical confinement, strong chemisorption, and catalytic enhancement to regulate sulfur redox behavior effectively. Within this system, MXene offers rich surface functionalities and excellent conductivity for LiPSs immobilization, while the ternary Zn-Co-Ni-S nanoparticles serve as active electrocatalysts that accelerate polysulfide conversion reactions. The CNTs further support continuous ion/electron transport and mitigate interfacial resistance. As a result, the multidimensional composite separator not only restrains polysulfide shuttling but also improves redox kinetics and cycling durability. Integrated architecture enables the battery to achieve a reversible capacity of 1333 mAh g^-1 under a current density of 0.2C. Under high-rate cycling conditions of 4.0C, the battery delivers considerable capacities of 569 mAh g^-1. At 1.0C, the battery initially discharges at 1043 mAh g^-1, and after a prolonged activation period, it exhibits a capacity decay of just 0.1 % per cycle, reflecting outstanding cycling stability.