Antimony Chalcogenide van der Waals Nanostructures for Energy Conversion and Storage

Among van der Waals nanomaterials, topological insulators such as antimony chalcogenides (Sb₂X₃, X = S, Se, Te) have interesting thermoelectric and optical properties. Expressly, Sb₂S₃ is regarded as a favorable anode material for batteries owing to its predicted specific capacity. Both Sb₂S₃ and Sb₂Se₃ have an isomorphous tubular one-dimensional (1D) crystal structure, whereas Sb₂Te₃ has a two-dimensional (2D) layered structure. The synthesized bulk crystals of Sb₂X₃ were submitted to liquid-phase shear force exfoliation. The 1D and 2D Sb₂X₃ undergo downsizing processes, also complemented by delamination, to submicron sheets and with an average thickness down to 37 nm. The inherent electrochemical and heterogeneous electron transfer properties of the materials were first studied. Exfoliated Sb₂S₃ had the best performance for the hydrogen evolution reaction in a wide pH range, with improvements in the overpotential of up to 500 mV, with respect to the starting material. Specifically, in acidic media, exfoliated Sb₂S₃ also has a good stability for multiple cycles and continuous operation. Likewise, exfoliated Sb₂S₃ had the highest gravimetric capacitive behavior in alkaline solution.