Correlated Dual‐Gradient Electrodes Enabling Spatially Synchronized Sulfur Redox in High‐Mass‐Loading Li–S Batteries Under High Current Densities

Abstract

ABSTRACT The practical deployment of Li–S batteries is hindered by sluggish redox kinetics and poor ion transport in high‐mass‐loading sulfur cathodes, especially under fast‐charging and high‐power‐density conditions. Conventional electrocatalyst‐based strategies partially mitigate electrochemical polarization by lowering reaction energy barriers but fail to address concentration and ohmic polarization, which become more pronounced in thick electrodes. Here, a coupled material‐architecture approach is demonstrated by integrating electrocatalysts into a low‐tortuosity, correlated dual‐gradient electrode, fabricated via programmable high‐resolution stereolithography and pyrolysis‐induced carbonization. The microscale pore gradient is deliberately correlated with the active‐material gradient to spatially synchronize redox progression across electrode depth, thereby homogenizing cathode utilization and alleviating concentration polarization. Pyrolysis generates additional nanoscale pores, establishing a hierarchical structure and transforming polymer‐salt precursors into a conductive carbon framework embedding Li 2 S@Fe 2 O 3 /Fe‐N‐C, enhancing ion accessibility and minimizing ohmic polarization, while Fe 2 O 3 /Fe‐N‐C accelerates polysulfide conversion, reducing electrochemical polarization. Benefiting from this synergy, the Li 2 S@Fe 2 O 3 /Fe‐N‐C electrode delivers high‐areal‐capacities of 22.7 mAh cm −2 (1048 mAh g −1 ) at 0.1 C, 15.7 mAh cm −2 (725 mAh g −1 ) at 5 C, and retains 82% capacity over 1100 cycles at 4 C. A single‐layer pouch cell achieves a specific energy of 403 Wh kg −1 , demonstrating the promise of this dual‐gradient strategy for real‐world high‐energy and high‐power Li–S batteries.