Vacancy‐Assisted Transformation of MoS2 Nanosheets into Defective MoSx Nanoclusters to Regulate Sodium‐Ion Electrode Functionality

Abstract Defect structure has attracted significant attention because of its importance as design factor for exploring high‐performance functional materials. This study reports a defect‐engineering strategy to optimize the electrode performance of transition metal dichalcogenides and a clear elucidation of the underlying mechanism on the benefit of defect engineering with cycling‐induced transformation into small nanoclusters. The intercalative hybridization of monolayered MoS 2 nanosheets with bulky tetraalkylammonium cations is effective for generating abundant crystal vacancies in the MoS 2 lattice and improving the sodium‐ion electrode performance, achieving one of the excellent performances among MoS 2 ‐based sodium‐ion anode materials. The improved electrode activity of the tetrapropylammonium−MoS 2 nanohybrid is ascribed to the vacancy‐assisted transformation from monolayered MoS 2 nanosheets into trimeric/dimeric MoS x nanoclusters during electrochemical cycling. 23 Na/ 1 H magic angle spinning‐nuclear magnetic resonance analyses demonstrated that cycling‐induced defective MoS x nanoclusters yields a complex Na environment with high ion mobility and enhanced electrolyte absorptivity, promoting the excellent electrode functionality of tetrapropylammonium‐assembled MoS 2 nanosheets.