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

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 beta-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 beta-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.