Dynamic Interface Reconstruction in Heterojunction Electrocatalysts Enables Radical-Mediated Sulfur Redox Kinetics for High-Energy Lithium–Sulfur Batteries

Lithium–sulfur batteries have attracted significant attention due to their ultrahigh theoretical energy density and cost-effectiveness. However, practical applications face critical challenges such as polysulfide shuttling and sluggish sulfur redox kinetics. This study proposes a design strategy that addresses these issues by constructing heterojunction electrocatalysts with dynamic interface reconstruction capabilities. The prepared indium-modified nitrogen-doped porous carbon composite (IZNC) demonstrates an enhanced bifunctional catalytic activity through in situ surface sulfidation. Comprehensive in situ/ex situ characterizations, along with theoretical calculations, reveal that the IZNC catalyst undergoes a phase transformation during initial cycles, forming an In2S3-rich interface. This interface not only firmly anchors polysulfides via In–S coupling but also induces the generation of trisulfide radical anions (Li2S3•–). Importantly, this radical-mediated pathway maintains kinetic advantages in conventional ether electrolytes, overcoming the limitations associated with high Gutmann donor number solvents. Experimental results show that the IZNC-based cathode delivers a high reversible capacity of 1135 mA h g–1 at 0.1 C and retains 61.7% of its capacity after 980 cycles at 3 C. Even under harsh conditions (4.5 mg cm–2 sulfur loading, E/S = 6 μL mg–1), the battery system exhibits a remarkable cycling performance. This work sets a benchmark for designing adaptive catalytic architectures and advances our understanding of dynamic heterojunction engineering.