Pulsed laser deposited heterogeneous mixture of Li2Se-Sb2Se3 nanocomposite as a new storage lithium material

Li₂Se-Sb₂Se₃ nanocomposites with a highly heterogeneous mixture have been fabricated by reactive pulsed laser deposition method. The electrochemical properties of the as-deposited Li₂Se-Sb₂Se₃ thin film during the first charging and discharging have been investigated by the galvanostatic cycling and cyclic voltammetry measurements for the first time. By using ex situ X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and selected-area electron diffraction (SAED) measurements, the decomposition of Li₂Se driven by Sb₂Se₃ under the electrochemical potential is revealed. In the first cycle, the oxidation peaks at 2.5 V and 3.2 V and the reduction peaks at 2.0 V can be attributed to the decomposition and formation of Li₂Se with the conversion reaction of Sb₂Se₃ into Sb₂Se₅. Our findings demonstrate that nanocomposite Li₂Se-Sb₂Se₃ can possess very high electrochemical activity. These results present a special case of solid-state heterogeneous electrochemistry with both nanostructured binary materials.