Accelerating Sulfur Redox Kinetics via 3D-Printed Multifunctional Cathodes for High-Energy-Density Lithium–Sulfur Batteries

Lithium-sulfur (Li-S) batteries are viewed as leading contenders for next-generation energy storage, offering high theoretical specific energy and cost-efficient materials; yet, their practical application is profoundly challenged by sluggish sulfur redox kinetics, polysulfide shuttling, and constrained sulfur loading. Herein, we unveil a versatile 3D-printed matrix, integrating in situ nitrogen (N)-doped carbon nanotubes (3DP NCNTs), designed to function as an efficient sulfur host (3DP S@NCNTs) for achieving high energy density in Li-S batteries. The meticulously engineered 3D hierarchical porous architecture, constructed from interwoven CNTs and precisely printed macropores, promotes efficient interfacial charge and mass transfer, enhanced mechanical integrity, and thorough electrolyte infiltration. Meanwhile, the electronegative N atoms on 3DP S@NCNTs electrodes significantly relieve the "shuttle effect" and boost the redox reaction kinetics of polysulfides through their strong affinity toward lithium polysulfides. Benefiting from these merits, the fabricated Li-S battery with 3DP S@NCNTs cathode achieves an exceptional areal specific capacity of 9.51 mAh cm^-2 under an ultrahigh sulfur mass loading of 10 mg cm^-2, along with excellent cycling stability over 250 cycles at 0.5 C. The integration of 3D-printed electrode architecture design with surface modification provides a groundbreaking approach to overcome the challenges facing thick electrodes, presenting a versatile strategy for the development of high-energy-density batteries.