Electrostatic Regulation of Sulfur Spatial Evolution for Dimensionally Stable Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries are promising for high-energy storage but are limited by complex multistep sulfur redox reactions that induce polysulfide migration, sluggish conversion kinetics, and severe cathode swelling. Here, we report a boron nitride/carbon nanotube (BN/CNT) heterostructure that enables electrostatic regulation of sulfur spatial evolution through the separation of polar domains and conductive networks. The conductive CNT scaffold preserves electron percolation, whereas the BN interlayer provides abundant polarity to regulate polysulfide interactions. Amine functionalization (BN-NH₂) further tailors the local electronic environment and interfacial charge distribution. Consequently, sulfur spatial evolution is regulated toward homogeneous redistribution rather than surface overaccumulation, resulting in near-zero cathode swelling during prolonged cycling. The optimized BN-NH₂/CNT configuration maintains a capacity of 1150 mAh g^-1 after 500 cycles and exhibits reduced polarization and enhanced rate capability. Potentiostatic nucleation analysis, nano-X-ray fluorescence mapping, depth-resolved X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy reveal stabilized sulfur redox chemistry and regulated sulfur electronic environments. Density functional theory calculations reveal interfacial charge redistribution and optimized interaction strengths that support regulated sulfur redox chemistry. In this work, moderated electrostatic regulation of sulfur spatial evolution is established as a design principle for dimensionally stable and kinetically optimized Li-S cathodes beyond adsorption-centric strategies.