Shape-controlled synthesis of β-In2S3 nanocrystals and their lithium storage properties

Abstract

The ability to control the shape and morphology of inorganic nanocrystals (NCs) is essential to the development of various NC-based functional devices. Here we report the shape-controlled synthesis of β-In₂S₃ NCs and elucidate how the NC shape and morphology affect their lithium storage properties when used as anode materials in lithium-ion batteries. Three representative types of β-In₂S₃ NCs with precisely-controlled morphologies, including one-dimensional (1D) nanotubes, 2D nanosheets, and 3D nanoflowers, are synthesized by a ligand-assisted route under similar reaction conditions. Mild thermal treatment converts the organic ligands attached to the NC surface into a conformal carbon-coating layer while preserving the NC shape, resulting in In₂S₃/C nanocomposites having similar carbon contents irrespective of their shape. This, combined with identical electrode formulation and test procedures, allows us to probe the influence of shape on the electrochemical performance of In₂S₃ NCs. Compared with 1D nanotubes and 3D nanoflowers, 2D In₂S₃ nanosheets exhibit significantly higher capacities and rate capabilities, which is primarily attributed to their unique 2D layered structures.