Spatial Electric Field Effect-Driven Efficient Sulfur Reduction Reaction

The uncontrolled diffusion of soluble polysulfides and their unregulated deposition of Li₂S are key causes of capacity decay and reduced Coulombic efficiency in lithium-sulfur batteries (LSBs). Here, we construct a hollow urchin-like NiCo₂O_4-xSe_x framework featuring high-curvature tips and a selenization-derived gradient outer layer, and introduce a synergistic regulation mechanism that couples spatial electric-field effects with electronic-structure modulation. The localized electric field induced by high-curvature tips drives polysulfides and Li⁺ to preferentially accumulate toward the tip regions along a potential gradient and initiates rapid interfacial conversion. Meanwhile, Se regulation optimizes the electronic structure of Co sites, which strengthens Co─S interactions and renders the polarization and cleavage of S─S bonds. As a result, the polysulfide reaction pathway is transformed from disordered diffusion into a spatially vectorial process: conversion is initiated at the tips, propagated within the inner layer, and finalized by controlled deposition on the inner side, effectively suppressing the shuttle effect and preventing rapid surface accumulation of Li₂S. Benefiting from this strategy, the cells deliver outstanding electrochemical performance under high-rate operation, prolonged cycling, and high sulfur loading. This work demonstrates that synergistic spatial electric-field engineering converts complex multistep interfacial reactions into a controllable spatial reaction process, offering a new avenue for LSBs.