Amorphization and Defect Engineering of Nb₂O₅ within a Graphitic Nanocage Array for Catalytic Polysulfide Conversion in Lithium-Sulfur Batteries

Abstract

Lithium-sulfur batteries (LSBs) are limited by lithium polysulfides (LiPS) shuttling and sluggish redox kinetics. To address this challenge, we design an amorphous, oxygen-deficient Nb₂O₅ embedded in a mesoporous graphitic framework (Nb₂O₅@MGF) as a multifunctional intelayer that strongly traps and catalytically converts LiPS. The Nb₂O₅@MGF uniformizes sulfur distribution, exposes vast active interfaces, and offers a reduced ion/electron transportation pathway for expedited redox reaction. Moreover, the amorphous Nb₂O₅ manipulates LiPS chemical affinity, while oxygen vacancies improve catalytic activity. Consequently, the Nb₂O₅@MGF-equipped cell exhibits high capacity and stable cycling. This work presents a synergistic crystallinity and defect-engineering strategy for practical LSBs.