Li1.1Cu0.9S is an intermediate phase in the electrochemical conversion reaction of CuS with Li and a potential environment-friendly battery and solar cell material. Yellow Li1.1Cu0.9S is a direct band-gap semiconductor and highly air and moisture sensitive. It was obtained by the reaction of CuS with a slight excess of Li metal. The crystal structure was solved using X-ray, neutron and 7Li NMR data. The compound crystallizes tetragonal in a novel structure type.
Figure 1: Crystal structure of Li1.1Cu0.9S. The metal sites, M, are occupied by randomly mixed Li and Cu atoms (left). 7Li solid state NMR and neutron powder diffraction pattern of Li1.1Cu0.9S (right).