Single‐Atom‐Stabilized Defects: Breaking the Activity–Stability Trade‐off in Li–S Battery Electrocatalysis

Abstract

The intrinsic activity–stability trade‐off has long plagued defect‐engineered electrocatalysts, as maximizing active sites via defect engineering typically compromises the lattice integrity of the host matrix. Herein, we propose a paradigm‐shifting “catalyst‐stabilized defects” strategy to fundamentally decouple this dilemma, wherein atomically dispersed metal sites act as both structural stabilizers and electronic modulators for defective matrices. Taking Nb single atoms anchored on vacancy‐rich TiO 2 nanosheets grown on carbon cloth (Nb/V‐T@CC) as a model system, we demonstrate that Nb single atoms thermodynamically reconfigure metastable vacancy clusters through strong metal–support interactions. This unique stabilization effect not only suppresses lattice collapse during long‐term cycling but also optimizes the electronic structure of the catalyst. The synergistic interplay between Nb single atoms and stabilized vacancy clusters upshifts the d ‐band center, enhances d ‐ p orbital hybridization with sulfur species, and reduces kinetic barriers for polysulfide conversion as well as Li 2 S nucleation and decomposition. When employed as both a current collector and sulfur host, the Nb/V‐T@CC catalyst achieves an ultra‐low‐capacity decay rate of 0.028% per cycle over 1000 cycles at 2.0 C. Furthermore, a flexible pouch cell based on this architecture achieves a high initial discharge capacity of 1.3 Ah while maintaining robust performance under repeated bending.