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

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 MoS2 nanosheets with bulky tetraalkylammonium cations is effective for generating abundant crystal vacancies in the MoS2 lattice and improving the sodium‐ion electrode performance, achieving one of the excellent performances among MoS2‐based sodium‐ion anode materials. The improved electrode activity of the tetrapropylammonium−MoS2 nanohybrid is ascribed to the vacancy‐assisted transformation from monolayered MoS2 nanosheets into trimeric/dimeric MoSx nanoclusters during electrochemical cycling. 23Na/1H magic angle spinning‐nuclear magnetic resonance analyses demonstrated that cycling‐induced defective MoSx nanoclusters yields a complex Na environment with high ion mobility and enhanced electrolyte absorptivity, promoting the excellent electrode functionality of tetrapropylammonium‐assembled MoS2 nanosheets. A defect‐engineering strategy is developed to optimize the electrode performance of transition metal dichalcogenides via cycling‐induced transformation into small trimeric/dimeric nanoclusters. The intercalative hybridization of MoS2 monolayers with bulky tetraalkylammonium cations is quite effective for optimizing the sodium‐ion electrode performance via the creation of plenty of crystal defects. This strategy provides a versatile way of exploring high‐performance conversion‐based anode materials.