Breaking Single‐Reaction Limits: In Situ Visualization of TiS ₂ ‐Driven Conversion‐Intercalation Synergy in Lithium‐Sulfur Batteries

Abstract

ABSTRACT Conventional cathodes of lithium battery relying on single storage mechanisms—whether intercalation or conversion—face intrinsic limitations in energy density and sluggish electrode kinetics. Hybrid systems combining both mechanisms offer promising pathways to transcend these constraints; yet, their dynamic interfacial synergies remain poorly deciphered at the nanoscale. This study employs multimodal in situ characterization (Electrochemical atomic force microscopy/Raman/Electrochemical impedance spectroscopy) to elucidate the dynamic synergy in TiS 2 ‐S hybrid cathodes, revealing the concurrent interfacial evolution during cycling: nanoscale steps formation via Li‐ion intercalation in the TiS 2 ‐LiTiS 2 host and the phase transformation of S‐Li 2 S/Li 2 S 2 . Crucially, the TiS 2 /LiTiS 2 serves as a bifunctional interface that not only contributes capacity but also mediates sulfide adsorption and catalyzes preferential edge‐directed sulfide deposition. The partially delithiated Li x TiS 2 enhances electronic conductivity, creating rapid electron transport that facilitates subsequent interfacial sulfide conversion reaction. The hybrid storage mechanism retains features characteristic of both S and TiS 2 storage mechanisms, yet manifests synergistic interfacial reconstruction rather than simple superposition, achieving enhanced reversibility, exceptional cycling stability, and superior rate capability.